Nanoporous polymers are extensively coated on various substrates to deliver optical,permselective,or other functions.However,it remains desired to fast produce uniform nanoporous polymer coatings on substrates with co...Nanoporous polymers are extensively coated on various substrates to deliver optical,permselective,or other functions.However,it remains desired to fast produce uniform nanoporous polymer coatings on substrates with complex surfaces.Herein,by manipulating the interactions between block copolymers and selective solvents,we prepare repairable nanoporous polymers on arbitrary substrates.This is realized by an extremely simple sequential coating process:sequential coating of block copolymers and their swelling agents on substrate surfaces.The swelling agents are comprised of two solvents that swell the constituent blocks of the copolymers to different degrees,rapidly producing polymer coatings with uniform,interconnected,sub-50 nm pores.This sequential coating process is able to conformally build nanoporous polymers on nonplanar substrates with large lateral sizes and complex surface features,and also to in situ repair defects arising during usages.We further demonstrate that the nanoporous coatings show excellent antireflective and membrane separation performances.This sequential coating process is dictated by polymer–solvent interactions,and is expected to find applications in diverse fields for its simplicity,adaptability,and the capability to produce well-defined nanoporosities.展开更多
The preparation and functionalization of polymeric capsules attract intense attention due to their application in various areas.Herein we presented an amphiphilic alternating copolymer(ACP)-based microcapsule which is...The preparation and functionalization of polymeric capsules attract intense attention due to their application in various areas.Herein we presented an amphiphilic alternating copolymer(ACP)-based microcapsule which is both robust and readily-functionalized through interfacial click polymerization.A water-in-oil emulsion was constructed to act as the reaction medium,the hydrophilic 1,3-butadiene diepoxide(BDE)in water phase reacted with the oleophilic 1,4-dibutanedithiol(BDT)in oil phase at the water-oil interface to form the amphiphilic ACP named poly(2,3-dihydroxy butylene-alt-butylene dithioether)(abbreviated as P(DHB-a-BDT)below),which would deposite in situ to form the micro-sized capsules.Significantly,the dried capsules are robust enough to be rehydrated once the water was added and almost restored their original morphologies.Further elucidation showed that the Young's modulus of these capsules exceeded 1 GPa.As long as we know,it is the first time for the mechanical properties of the ACP-based microstructures being investigated.Besides,functionalization could be achieved simultaneously with the formation process.As a proof of concept,positive-charged capsules were successfully obtained through click copolymerization.Stemming from the unique characteristics of amphiphilic ACPs which combined both merits of click chemistry and interfacial reactions,all these features of the current method as well as the resultant capsules may promote the application of the polymeric capsules.展开更多
The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytot...The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytotoxicity.These limitations have catalyzed the development of intelligent stimuli-responsive block copolymers-based bioimaging agents,which was engineered to dynamically respond to endogenous biochemical cues(e.g.,p H gradients,redox potential,enzyme activity,hypoxia environment) or exogenous physical triggers(e.g.,photoirradiation,thermal gradients,ultrasound(US)/magnetic stimuli).Through spatiotemporally controlled structural transformations,stimuli-responsive block copolymers enable precise contrast targeting,activatable signal amplification,and theranostic integration,thereby substantially enhancing signal-to-noise ratios of bioimaging and diagnostic specificity.Hence,this mini-review systematically examines molecular engineering principles for designing p H-,redox-,enzyme-,light-,thermo-,and US/magnetic-responsive polymers,with emphasis on structure-property relationships governing imaging performance modulation.Furthermore,we critically analyze emerging strategies for optical imaging,US synergies,and magnetic resonance imaging(MRI).Multimodal bioimaging has also been elaborated,which could overcome the inherent trade-offs between resolution,penetration depth,and functional specificity in single-modal approaches.By elucidating mechanistic insights and translational challenges,this mini-review aims to establish a design framework of stimuli-responsive block copolymersbased for high fidelity bioimaging agents and accelerate their clinical translation in precise diagnosis and therapy.展开更多
Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford prod...Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.展开更多
Star-shaped six-arm polymers with hexaaza[2_(6)]orthoparacyclophane core and arms of block copolymers of poly-2-ethyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine were synthesized successfully using cat...Star-shaped six-arm polymers with hexaaza[2_(6)]orthoparacyclophane core and arms of block copolymers of poly-2-ethyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine were synthesized successfully using cationic ring-opening polymerization.The ratio of blocks,the order of their attachment to the core,and arm length were varied.Conformation of synthesized stars was determined by methods of molecular hydrodynamics and optics.It has been shown that star-shaped molecules were characterized by high intramolecular density,and the arm folding increased with their lengthening.The influence of the structure of block copolymers and their molar mass on the critical micelle concentration has been established.Complexes of synthesized star-shaped block copolymers with curcumin were obtained and the efficient binding of curcumin to polymer molecules was demonstrated.The behavior of the aqueous solutions of the prepared polymer stars and their complexes with curcumin was investigated by light scattering and turbidimetry methods.The influence of the structure and molar mass of star polymers on their thermoresponsiveness and the phase separation temperatures in aqueous solutions was analyzed.A slight increase in the phase separation temperature was found on passage from polymer solutions to solutions of polymer complexes with hydrophobic curcumin.展开更多
In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were inve...In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were investigated.The results showed that the three materials had satisfactory compatibility in the composite film.Addition of EC and zein effectively improved the mechanical properties,thermodynamic properties,surface hydrophilicity,oxygen permeability,and degradation properties of PLA films.When the ratio of PLA to EC was 3:7,the tensile strength and elongation at break reached maximum values of 16.6 MPa and 30.5%,respectively.Moreover,under different conditions,the composite film exhibited better degradability than the PLA film.The composite film with a 3:7 ratio of PLA to EC had the best performance,with a degradation rate of 21.75%after 84 days.Chilled fresh meat wrapped with the composite film showed significantly improved antioxidant,antibacterial,and water-holding properties.展开更多
Increasing environmental concerns about limiting harmful emissions has necessitated sulfur-and phosphorus-free green lubricant additives.Although boron-containing compounds have been widely investigated as green lubri...Increasing environmental concerns about limiting harmful emissions has necessitated sulfur-and phosphorus-free green lubricant additives.Although boron-containing compounds have been widely investigated as green lubricant additives,their macromolecular analogs have been rarely considered yet to develop environmentally friendly lubricant additives.In this work,a series of boron-containing copolymers have been synthesized by free-radical copolymerization of stearyl methacrylate and isopropenyl boronic acid pinacol ester with different feeding ratios(S_(n)-r-B_(m),n=1,m=1/3,1,2,3,5,9).The resulting copolymers of S_(n)-r-B_(m)(n=1,m=1/3,1,2,3,5)are readily dispersed in the PAO-10 base oil and form micelle-like aggregates with hydrodynamic diameters ranging from 9.7 to 52 nm.SRV-IV oscillating reciprocating tribological tests on ball-on-flat steel pairs show that compared with the base oil of PAO-10,the friction coefficients and wear volumes of the base oil solutions of S_(n)-r-B_(m)decrease considerably up to 62%and 97%,respectively.Moreover,the base oil solution of S_(1)-r-B_(1)exhibits an excellent load-bearing capacity of(850±100)N.These superior lubricating properties are due to the formation of protective tribofilms comprising S_(n)-r-B_(m),boron oxide,and iron oxide compounds on the lubricated steel surface.Therefore,the boron-containing copolymers can be regarded as a novel class of environmentally friendly lubricating oil macroadditives for efficient friction and wear reduction without sulfur and phosphorus elements.展开更多
Polylactic acid(PLA),a biodegradable polymer,exhibits superior mechanical strength and processability.However,its broader adoption is hindered by inherent brittleness,low hydrophilicity,and sluggish crystallization ki...Polylactic acid(PLA),a biodegradable polymer,exhibits superior mechanical strength and processability.However,its broader adoption is hindered by inherent brittleness,low hydrophilicity,and sluggish crystallization kinetics.Chitosan(CS),a natural polysaccharide renowned for its biocompatibility and biodegradability,offers potential to address these limitations.While both materials have garnered significant attention in materials science,research on their integration via melt blending and the resulting performance enhancements for food-contact plastics remains understudied.This research comprehensively explores how different levels of CS content,from 0% to 10%,impact the characteristics of chitosan/polylactic acid(CS/PLA)composites.It specifically analyzes the influence of various CS concentrations on the mechanical attributes,crystallization behavior,thermomechanical properties,and rheological performance of these composites.The study concludes that a CS content of 4% in the CS/PLA composite results in the best overall properties.At this point,its elongation at break and impact strength reached theirmaximum values(16.16% and 20.63 kJ/m^(2)),representing increases of 23.9% and 15.7% compared to pure PLA.At this particular concentration,CS is evenly distributed throughout the PLA matrix,acting as a heterogeneous nucleating agent.It facilitates the crystallization of the composite material and offers effective reinforcement.This study presents a promising approach for developing environmentally friendly and sustainable alternatives to fossil-based plastics,highlighting significant research value and practical application potential.展开更多
Nanomaterials are extensively utilized in a multitude of sectors,but their propensity to aggregate can considerably diminish the efficacy of functional materials.A pivotal challenge in this domain is achieving a homog...Nanomaterials are extensively utilized in a multitude of sectors,but their propensity to aggregate can considerably diminish the efficacy of functional materials.A pivotal challenge in this domain is achieving a homogenous distribution of nanomaterials,which is essential for enhancing their performance while also reducing production costs.In this work,we achieve uniform and stable dispersion of various nano-materials through the confinement effect generated by the stereocomplex cross-linked network formed by the combination of poly(L-lactic)acid and poly(D-lactic)acid.The unique confinement effect of poly-lactic acid(PLA)isomers is universal and significantly enhances the dispersion of nanomaterials in both PLA solutions and films.To demonstrate the efficacy of our approach,we disperse aggregation-induced emission(AIE)molecules within PLA,which leads to the production of PLA films exhibiting improved fluorescence property.This work provides an effective solution for the preparation of nanocomposite ma-terials that are both high-performing and cost-efficient.展开更多
Alcoholysis is one of the most effective methods for recycling polyester plastics.While many researchers claim that both alcohol and polymer reactants are activated simultaneously in the alcoholysis reaction,more reli...Alcoholysis is one of the most effective methods for recycling polyester plastics.While many researchers claim that both alcohol and polymer reactants are activated simultaneously in the alcoholysis reaction,more reliable experimental evidence is needed to fully understand the process,and the catalytic mechanism remains elusive.To address this issue,we proposed a reactant-modulated catalytic depolymerization strategy involving a pre-mixing of alcohol or polylactic acid(PLA)with an organic base catalyst.Through systematic experimental and theoretical investigations,we have confirmed that different intermediates are formed during pre-mixing the catalyst with PLA or methanol,which can either slow down or accelerate the subsequent alcoholysis reaction.By employing the methanol-modulated depolymerization technique,we successfully achieved PLA alcoholysis at temperatures as low as–40℃.We further investigated the solubility and reactivity of different polyesters,including PET,PC,PBS,PBAT,PCL,and PLA,revealing an efficient recycling method for PLA.By optimizing reaction conditions in a continuous flow reactor,we recovered 127.3 g of methyl lactate from 100 g of plastic cups in just 4 h at room temperature.These findings greatly improve our grasp of polyester solvolysis processes and create new opportunities within the plastics sector recycling.展开更多
Amphiphilic asymmetric brush copolymers(AABCs)possess unique self-assembly behaviors owing to their asymmetric brush architecture and multiple functionalities of multicomponent side chains.However,the synthesis of AAB...Amphiphilic asymmetric brush copolymers(AABCs)possess unique self-assembly behaviors owing to their asymmetric brush architecture and multiple functionalities of multicomponent side chains.However,the synthesis of AABCs presents challenges,which greatly limits the exploration of their self-assembly behaviors.In this work,we employed dissipative particle dynamics(DPD)simulations to investigate the self-assembly behaviors of AABCs in selective solution.By varying the copolymer concentration and structure,we conducted the self-assembly phase diagrams of AABCs,revealing complex morphologies such as channelized micelles with one or more solvophilic channels.Moreover,the number,surface area,and one-dimensional density distribution of the channelized micelles were calculated to demonstrate the internal structure and morphological transformation during the self-assembly process.Our findings indicate that the morphology of the internal solvophilic channels is greatly influenced by the copolymer structure,concentration,and interaction parameters between the different side chains.The simulation results are consistent with available experimental observations,which can offer theoretical insights into the self-assembly of AABCs.展开更多
A significant challenge in developing block copolymer photonic crystals is constructing low-symmetric ordered phases,which are essential for achieving a complete photonic band gap.Here,we propose a promising strategy ...A significant challenge in developing block copolymer photonic crystals is constructing low-symmetric ordered phases,which are essential for achieving a complete photonic band gap.Here,we propose a promising strategy to create low-symmetric ordered morphologies by incorporating shape-anisotropic rod-like side chains into block copolymers.Using dissipative particle dynamics simulations,we demonstrate that block copolymers with longer rod-like side chains can self-assemble into a hexagonally packed columnar phase characterized by a low-symmetric rectangular cross-section.Photonic band structure calculations reveal that this low-symmetric columnar phase can exhibit a complete photonic band gap,with the gap size dependent on the aspect ratio of the rectangular cross-sections of the columns.Our findings suggest an effective approach to constructing low-symmetric photonic crystals through the self-assembly of block copolymers with shape-anisotropic segments.展开更多
The design of low-cost and high-performance cyclic olefin copolymers remains challenging.Ethylene copolymers with dicyclopentadiene(DCPD)were prepared using Ph_(2)C(Cp)(Flu)ZrCl_(2)(Cat.1),rac-Et(Ind)_(2)ZrCl_(2)(Cat....The design of low-cost and high-performance cyclic olefin copolymers remains challenging.Ethylene copolymers with dicyclopentadiene(DCPD)were prepared using Ph_(2)C(Cp)(Flu)ZrCl_(2)(Cat.1),rac-Et(Ind)_(2)ZrCl_(2)(Cat.2),Me_(2)C(Cp)(Flu)ZrCl_(2)(Cat.3)andMe_(2)Si(Ind)_(2)ZrCl_(2)(Cat.4)combined with[Ph_(3)C][B(C_(6)F_(5))_(4)]/iBu_(3)Al.Ni(acac)_(2)/iBu_(3)Al was then used to catalyze the hydrogenation of the intracyclic double bonds of ethylene/DCPD copolymers.The results showed that compared to C_(2) symmetric catalysts(Cat.2 and Cat.4),Cs symmetric catalysts(Cat.1 and Cat.3)facilitated the incorporation of copolymers with higher DCPD.1H-and ^(13)C-NMR spectra indicated that ethylene/DCPD copolymerization occurred via enhancement of the norbornene ring.Additionally,measurement of the reactivity ratios provided further confirmation that the copolymers had random sequence distributions.All these samples demonstrated transmittance values above 90%in the visible wavelength range from 400 nm to 800 nm.By changing the fraction of monomers,the glass transition temperature,refractive index,Young's modulus,and tensile strength of the copolymer increased as the incorporation of DCPD increased,whereas the Abbe number and elongation at break decreased.Compared with ethylene/norbornene and ethylene/tetracyclicdodecene copolymers,ethylene/DCPD copolymers,with excellent optical and mechanical properties,are promising materials.展开更多
The optimization of polymer structures aims to determine an optimal sequence or topology that achieves a given target property or structural performance.This inverse design problem involves searching within a vast com...The optimization of polymer structures aims to determine an optimal sequence or topology that achieves a given target property or structural performance.This inverse design problem involves searching within a vast combinatorial phase space defined by components,se-quences,and topologies,and is often computationally intractable due to its NP-hard nature.At the core of this challenge lies the need to evalu-ate complex correlations among structural variables,a classical problem in both statistical physics and combinatorial optimization.To address this,we adopt a mean-field approach that decouples direct variable-variable interactions into effective interactions between each variable and an auxiliary field.The simulated bifurcation(SB)algorithm is employed as a mean-field-based optimization framework.It constructs a Hamiltonian dynamical system by introducing generalized momentum fields,enabling efficient decoupling and dynamic evolution of strongly coupled struc-tural variables.Using the sequence optimization of a linear copolymer adsorbing on a solid surface as a case study,we demonstrate the applica-bility of the SB algorithm to high-dimensional,non-differentiable combinatorial optimization problems.Our results show that SB can efficiently discover polymer sequences with excellent adsorption performance within a reasonable computational time.Furthermore,it exhibits robust con-vergence and high parallel scalability across large design spaces.The approach developed in this work offers a new computational pathway for polymer structure optimization.It also lays a theoretical foundation for future extensions to topological design problems,such as optimizing the number and placement of side chains,as well as the co-optimization of sequence and topology.展开更多
Spatial confinement of block copolymers can induce frustrations,which can further be utilized to regulate self-assembled structures,thus providing an efficient route for fabricating novel structures.We studied the sel...Spatial confinement of block copolymers can induce frustrations,which can further be utilized to regulate self-assembled structures,thus providing an efficient route for fabricating novel structures.We studied the self-assembly of AB di-block copolymers(di-BCPs)confined in Janus spherical nanocavities using simulations,and explained the structure formation mechanisms.In the case of a strongly selective cavity wall,all the lamella-forming,gyroid-forming,and cylinder-forming di-BCPs can form interfacial frustration-induced Janus concentric perforated lamellar nanoparticles,whose outermost is a Janus spherical shell and the internal is a sphere with concentric perforated lamellar structure.In particular,Janus concentric perforated lamellar nanoparticles with holes distributed only near the equatorial plane were obtained in both lamella-forming and gyroid-forming di-BCPs,directly reflecting the effect of interfacial frustration.The minority-block domain of the cylider-forming di-BCPs may form hemispherical perforated lamellar structures with holes distributed in parallel layers with a specific orientation.For symmetric di-BCPs,both the A and B domains in each nanoparticle are continuous,interchangeable,and have rotational symmetry.While for gyroid-forming and cylinder-forming di-BCPs,only the majority-block domains are continuous in each nanoparticle,and holes in the minority-block domains usually have rotational symmetry.In the case of a weakly selective cavity wall,the inhomogeneity of the cavity wall results in structures having a specific orientation(such as flower-like and branched structures in gyroid-forming and cylinder-forming di-BCPs)and a perforated wetting layer with uniformly distributed holes.The novel nanoparticles obtained may have potential applications in nanotechnology as functional nanostructures or nanoparticles.展开更多
Polymers that exhibit both biodegradability and chemical recyclability offer a promising solution to environmental pollution and resource scarcity. Poly(glycolic acid)(PGA) is a promising chemically recyclable polymer...Polymers that exhibit both biodegradability and chemical recyclability offer a promising solution to environmental pollution and resource scarcity. Poly(glycolic acid)(PGA) is a promising chemically recyclable polymer, characterized by its seawater degradability and high mechanical strength. In this study, aliphatic polycarbonates were synthesized through melt polycondensation and subsequently copolymerized with glycolide(GL) to produce chemically recyclable PGA based triblock copolymers with well-defined structures. The properties of these copolymers, including their thermal properties, crystallization behavior, and mechanical performance, can be effectively adjusted by modifying the structure and content of the middle block. Furthermore, an in-depth investigation reveals that the pyrolysis process involves ester exchange, radical, and back-biting reactions. In addition, the high-efficiency "Monomer↔Copolymer" chemical recycling loop has been established, achieving a remarkable yield exceeding 88% along with a purity greater than 99%.展开更多
Cutting-edge research has primarily focused on flow synthesis of linear block copolymers,lacking the ability for manipulating chain architectures for more extensive applications.Herein,we develop a flow chemistry plat...Cutting-edge research has primarily focused on flow synthesis of linear block copolymers,lacking the ability for manipulating chain architectures for more extensive applications.Herein,we develop a flow chemistry platform for the continuous microflow synthesis of bottlebrush block copolymers(BBCPs)using a grafting-through method.This involves performing ring-opening metathesis polymerization(ROMP)of two different macromonomers within two microfluidic reactors connected in series.The microflow environment allows for complete monomer conversion within a few tens of seconds,benefiting from the superior mixing efficiency achieved in Z-shaped channels as indicated by both theoretical simulations and experimental results.Consequently,a library of well-defined BBCPs of up to 528 distinct samples can be produced within one day through automation of the continuous procedure,while keeping precise control on degree of polymerization(DP<4)and polydispersity indices(PDI<1.2).The synthetic method is generally applicable to different macromonomers with different compositions and contour lengths,yielding libraries of branched block copolymers with great diversity in physiochemical properties and chain architectures.This work presents a powerful platform for high-throughput production of branched copolymers,significantly lowering the costs of the materials for real applications.展开更多
Block copolymer(BCP) nanolithography offers potential beyond traditional photolithographic limits, yet reliably producing low-defect, perpendicular domains remains challenging. We introduce a microenvironmentdriven is...Block copolymer(BCP) nanolithography offers potential beyond traditional photolithographic limits, yet reliably producing low-defect, perpendicular domains remains challenging. We introduce a microenvironmentdriven isothermal annealing method for directed self-assembly of BCP thin films. By annealing films at stable temperature in a quasi-sealed, inert-gas chamber, our approach promotes highly uniform perpendicular lamellar nanopatterns over large areas, effectively mitigating environmental fluctuations and emulating solvent-vapor annealing without solvent exposure. Resulting BCP structures demonstrate enhanced spatial coherence and notably low defect density. Furthermore, we successfully transfer these nanopatterns into precise metal nano-line arrays,confirming the method's capability for high-fidelity pattern replication. This scalable, solvent-free technique provides a robust, reliable route for high-resolution nanopatterning in advanced semiconductor manufacturing.展开更多
Diblock copolymer poly(ethylene glycol) methyl ether–polylactide (MePEG–PLA) micelles were prepared by dialysis against water. Indomethacin (IMC) as a model drug was entrapped into the micelles by dialysis method. T...Diblock copolymer poly(ethylene glycol) methyl ether–polylactide (MePEG–PLA) micelles were prepared by dialysis against water. Indomethacin (IMC) as a model drug was entrapped into the micelles by dialysis method. The critical micelle concentration (CMC) of the prepared micelles in distilled water investigated by fluorescence spectroscopy was 0.0051 mg/mL which is lower than that of common low molecular weight surfactants. The diameters of MePEGPLA micelles and IMC loaded MePEGPLA micelles in a number-averaged scale measured by dynamic light scattering were 52.4 and 53.7 nm respectively. The observation with transmission electron microscope and scanning electron microscope showed that the appearance of MePEGPLA micelles was in a spherical shape. The content of IMC incorporated in the core portion of the micelles was 18% (ω). The effects of the synthesis method of the copolymer on the polydispersity of the micelles and the yield of the micelles formation were discussed.展开更多
Aim Ciprofloxacin polylactic acid microspheres (CFX-PLA-MS) were preparedusing solvent evaporation method from a solid-in-oil-in-water emulsion system. Methods Orthogonalexperiment was used to optimize the method of C...Aim Ciprofloxacin polylactic acid microspheres (CFX-PLA-MS) were preparedusing solvent evaporation method from a solid-in-oil-in-water emulsion system. Methods Orthogonalexperiment was used to optimize the method of CFX-PLA-MS preparation. Microspheres werecharacterized in terms of morphology, size, encapsulation efficiency, drug loading and in vitro drugrelease. Results The physical state of CFX-PLA-MS was determined by scanning electron microscopy(SEM) and differential scanning calorimetry (DSC) . Microspheres formed were spherical with smoothsurfaces. Drug was enveloped in microspheres without mixing physically with PLA. The averageparticle size was 280.80 ± 0.15 μm, with over 90% of microspheres falling in the range of 250 -390 μm. The encapsulation efficiency was 65.8% ± 0.58% and the drug loading was 34.1% ± 0.51% .In vitro release study revealed a profile of sustained release of Ciprofloxacin from CFX-PLA-MS. Theaccumulated release percentage and half-life (T_(1/2) of Ciprofloxacin microspheres were 84.0% in53.2 h, and 31.9 h, respectively. Higuchi equation was Q= -0.0043 + 0.003 9 t^(1/2), r = 0.9941.Conclusion Ciprofloxacin microspheres have been successfully prepared and sustained release of CFXfrom microspheres is achieved.展开更多
基金support from National Science Foundation of China(22438005)the Natural Science Foundation of Jiangsu Province(BE2022056-3)is gratefully acknowledged.
文摘Nanoporous polymers are extensively coated on various substrates to deliver optical,permselective,or other functions.However,it remains desired to fast produce uniform nanoporous polymer coatings on substrates with complex surfaces.Herein,by manipulating the interactions between block copolymers and selective solvents,we prepare repairable nanoporous polymers on arbitrary substrates.This is realized by an extremely simple sequential coating process:sequential coating of block copolymers and their swelling agents on substrate surfaces.The swelling agents are comprised of two solvents that swell the constituent blocks of the copolymers to different degrees,rapidly producing polymer coatings with uniform,interconnected,sub-50 nm pores.This sequential coating process is able to conformally build nanoporous polymers on nonplanar substrates with large lateral sizes and complex surface features,and also to in situ repair defects arising during usages.We further demonstrate that the nanoporous coatings show excellent antireflective and membrane separation performances.This sequential coating process is dictated by polymer–solvent interactions,and is expected to find applications in diverse fields for its simplicity,adaptability,and the capability to produce well-defined nanoporosities.
基金financially supported by the Fundamental Research Funds for Central Universities(No.24D110627)。
文摘The preparation and functionalization of polymeric capsules attract intense attention due to their application in various areas.Herein we presented an amphiphilic alternating copolymer(ACP)-based microcapsule which is both robust and readily-functionalized through interfacial click polymerization.A water-in-oil emulsion was constructed to act as the reaction medium,the hydrophilic 1,3-butadiene diepoxide(BDE)in water phase reacted with the oleophilic 1,4-dibutanedithiol(BDT)in oil phase at the water-oil interface to form the amphiphilic ACP named poly(2,3-dihydroxy butylene-alt-butylene dithioether)(abbreviated as P(DHB-a-BDT)below),which would deposite in situ to form the micro-sized capsules.Significantly,the dried capsules are robust enough to be rehydrated once the water was added and almost restored their original morphologies.Further elucidation showed that the Young's modulus of these capsules exceeded 1 GPa.As long as we know,it is the first time for the mechanical properties of the ACP-based microstructures being investigated.Besides,functionalization could be achieved simultaneously with the formation process.As a proof of concept,positive-charged capsules were successfully obtained through click copolymerization.Stemming from the unique characteristics of amphiphilic ACPs which combined both merits of click chemistry and interfacial reactions,all these features of the current method as well as the resultant capsules may promote the application of the polymeric capsules.
基金supported by the National Natural Science Foundation of China (Nos.22208218,22078196,and 22278268)the Natural Science Foundation of Shanghai (No.22ZR1460400)Collaborative Innovation Center of Fragrance Flavour and Cosmetics,and Collaborative Innovation Project of Shanghai Institute of Technology (No.XTCX2023-07)。
文摘The diagnostic efficacy of contemporary bioimaging technologies remains constrained by inherent limitations of conventional imaging agents,including suboptimal sensitivity,off-target biodistribution,and inherent cytotoxicity.These limitations have catalyzed the development of intelligent stimuli-responsive block copolymers-based bioimaging agents,which was engineered to dynamically respond to endogenous biochemical cues(e.g.,p H gradients,redox potential,enzyme activity,hypoxia environment) or exogenous physical triggers(e.g.,photoirradiation,thermal gradients,ultrasound(US)/magnetic stimuli).Through spatiotemporally controlled structural transformations,stimuli-responsive block copolymers enable precise contrast targeting,activatable signal amplification,and theranostic integration,thereby substantially enhancing signal-to-noise ratios of bioimaging and diagnostic specificity.Hence,this mini-review systematically examines molecular engineering principles for designing p H-,redox-,enzyme-,light-,thermo-,and US/magnetic-responsive polymers,with emphasis on structure-property relationships governing imaging performance modulation.Furthermore,we critically analyze emerging strategies for optical imaging,US synergies,and magnetic resonance imaging(MRI).Multimodal bioimaging has also been elaborated,which could overcome the inherent trade-offs between resolution,penetration depth,and functional specificity in single-modal approaches.By elucidating mechanistic insights and translational challenges,this mini-review aims to establish a design framework of stimuli-responsive block copolymersbased for high fidelity bioimaging agents and accelerate their clinical translation in precise diagnosis and therapy.
基金financially supported by National Key R&D Program Young Scientists Project(No.2023YFC3903100)the National Natural Science Foundation of China(No.22322503)analytical and testing assistance from the Analysis and Testing Center of HUST。
文摘Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.
基金financially supported by the Russian Science Foundation(No.23-13-00205)。
文摘Star-shaped six-arm polymers with hexaaza[2_(6)]orthoparacyclophane core and arms of block copolymers of poly-2-ethyl-5,6-dihydrooxazine with poly-2-isopropyl-5,6-dihydrooxazine were synthesized successfully using cationic ring-opening polymerization.The ratio of blocks,the order of their attachment to the core,and arm length were varied.Conformation of synthesized stars was determined by methods of molecular hydrodynamics and optics.It has been shown that star-shaped molecules were characterized by high intramolecular density,and the arm folding increased with their lengthening.The influence of the structure of block copolymers and their molar mass on the critical micelle concentration has been established.Complexes of synthesized star-shaped block copolymers with curcumin were obtained and the efficient binding of curcumin to polymer molecules was demonstrated.The behavior of the aqueous solutions of the prepared polymer stars and their complexes with curcumin was investigated by light scattering and turbidimetry methods.The influence of the structure and molar mass of star polymers on their thermoresponsiveness and the phase separation temperatures in aqueous solutions was analyzed.A slight increase in the phase separation temperature was found on passage from polymer solutions to solutions of polymer complexes with hydrophobic curcumin.
文摘In this study,composite films consisting of polylactic acid(PLA),ethyl cellulose(EC),and zein were prepared by solution casting method,and their performance and application in chilled fresh meat preservation were investigated.The results showed that the three materials had satisfactory compatibility in the composite film.Addition of EC and zein effectively improved the mechanical properties,thermodynamic properties,surface hydrophilicity,oxygen permeability,and degradation properties of PLA films.When the ratio of PLA to EC was 3:7,the tensile strength and elongation at break reached maximum values of 16.6 MPa and 30.5%,respectively.Moreover,under different conditions,the composite film exhibited better degradability than the PLA film.The composite film with a 3:7 ratio of PLA to EC had the best performance,with a degradation rate of 21.75%after 84 days.Chilled fresh meat wrapped with the composite film showed significantly improved antioxidant,antibacterial,and water-holding properties.
文摘Increasing environmental concerns about limiting harmful emissions has necessitated sulfur-and phosphorus-free green lubricant additives.Although boron-containing compounds have been widely investigated as green lubricant additives,their macromolecular analogs have been rarely considered yet to develop environmentally friendly lubricant additives.In this work,a series of boron-containing copolymers have been synthesized by free-radical copolymerization of stearyl methacrylate and isopropenyl boronic acid pinacol ester with different feeding ratios(S_(n)-r-B_(m),n=1,m=1/3,1,2,3,5,9).The resulting copolymers of S_(n)-r-B_(m)(n=1,m=1/3,1,2,3,5)are readily dispersed in the PAO-10 base oil and form micelle-like aggregates with hydrodynamic diameters ranging from 9.7 to 52 nm.SRV-IV oscillating reciprocating tribological tests on ball-on-flat steel pairs show that compared with the base oil of PAO-10,the friction coefficients and wear volumes of the base oil solutions of S_(n)-r-B_(m)decrease considerably up to 62%and 97%,respectively.Moreover,the base oil solution of S_(1)-r-B_(1)exhibits an excellent load-bearing capacity of(850±100)N.These superior lubricating properties are due to the formation of protective tribofilms comprising S_(n)-r-B_(m),boron oxide,and iron oxide compounds on the lubricated steel surface.Therefore,the boron-containing copolymers can be regarded as a novel class of environmentally friendly lubricating oil macroadditives for efficient friction and wear reduction without sulfur and phosphorus elements.
基金funded by National Natural Science Foundation of China(NSFC),grant number(No.U2341237).
文摘Polylactic acid(PLA),a biodegradable polymer,exhibits superior mechanical strength and processability.However,its broader adoption is hindered by inherent brittleness,low hydrophilicity,and sluggish crystallization kinetics.Chitosan(CS),a natural polysaccharide renowned for its biocompatibility and biodegradability,offers potential to address these limitations.While both materials have garnered significant attention in materials science,research on their integration via melt blending and the resulting performance enhancements for food-contact plastics remains understudied.This research comprehensively explores how different levels of CS content,from 0% to 10%,impact the characteristics of chitosan/polylactic acid(CS/PLA)composites.It specifically analyzes the influence of various CS concentrations on the mechanical attributes,crystallization behavior,thermomechanical properties,and rheological performance of these composites.The study concludes that a CS content of 4% in the CS/PLA composite results in the best overall properties.At this point,its elongation at break and impact strength reached theirmaximum values(16.16% and 20.63 kJ/m^(2)),representing increases of 23.9% and 15.7% compared to pure PLA.At this particular concentration,CS is evenly distributed throughout the PLA matrix,acting as a heterogeneous nucleating agent.It facilitates the crystallization of the composite material and offers effective reinforcement.This study presents a promising approach for developing environmentally friendly and sustainable alternatives to fossil-based plastics,highlighting significant research value and practical application potential.
基金supported by the National Key R&D Program of China(No.2022YFB3804204)the National Natural Science Foundation of China(Nos.52127805,52102090,12172005,and 12325202)+1 种基金the Fundamental Research Funds for the Central Uni-versities(No.2232022D-04)the Innovation and Development Sup-port Plan for Key Industries in Southern Xinjiang(No.2022DB011).
文摘Nanomaterials are extensively utilized in a multitude of sectors,but their propensity to aggregate can considerably diminish the efficacy of functional materials.A pivotal challenge in this domain is achieving a homogenous distribution of nanomaterials,which is essential for enhancing their performance while also reducing production costs.In this work,we achieve uniform and stable dispersion of various nano-materials through the confinement effect generated by the stereocomplex cross-linked network formed by the combination of poly(L-lactic)acid and poly(D-lactic)acid.The unique confinement effect of poly-lactic acid(PLA)isomers is universal and significantly enhances the dispersion of nanomaterials in both PLA solutions and films.To demonstrate the efficacy of our approach,we disperse aggregation-induced emission(AIE)molecules within PLA,which leads to the production of PLA films exhibiting improved fluorescence property.This work provides an effective solution for the preparation of nanocomposite ma-terials that are both high-performing and cost-efficient.
文摘Alcoholysis is one of the most effective methods for recycling polyester plastics.While many researchers claim that both alcohol and polymer reactants are activated simultaneously in the alcoholysis reaction,more reliable experimental evidence is needed to fully understand the process,and the catalytic mechanism remains elusive.To address this issue,we proposed a reactant-modulated catalytic depolymerization strategy involving a pre-mixing of alcohol or polylactic acid(PLA)with an organic base catalyst.Through systematic experimental and theoretical investigations,we have confirmed that different intermediates are formed during pre-mixing the catalyst with PLA or methanol,which can either slow down or accelerate the subsequent alcoholysis reaction.By employing the methanol-modulated depolymerization technique,we successfully achieved PLA alcoholysis at temperatures as low as–40℃.We further investigated the solubility and reactivity of different polyesters,including PET,PC,PBS,PBAT,PCL,and PLA,revealing an efficient recycling method for PLA.By optimizing reaction conditions in a continuous flow reactor,we recovered 127.3 g of methyl lactate from 100 g of plastic cups in just 4 h at room temperature.These findings greatly improve our grasp of polyester solvolysis processes and create new opportunities within the plastics sector recycling.
基金supported by the National Science Foundation for Distinguished Young Scholars(No.52325308)the National Natural Science Foundation of China(Nos.52273008 and 52073092)+1 种基金Shanghai Scientific and Technological Innovation Projects(No.22ZR1479300)Shanghai Rising-Star Program(No.23QA1402500).
文摘Amphiphilic asymmetric brush copolymers(AABCs)possess unique self-assembly behaviors owing to their asymmetric brush architecture and multiple functionalities of multicomponent side chains.However,the synthesis of AABCs presents challenges,which greatly limits the exploration of their self-assembly behaviors.In this work,we employed dissipative particle dynamics(DPD)simulations to investigate the self-assembly behaviors of AABCs in selective solution.By varying the copolymer concentration and structure,we conducted the self-assembly phase diagrams of AABCs,revealing complex morphologies such as channelized micelles with one or more solvophilic channels.Moreover,the number,surface area,and one-dimensional density distribution of the channelized micelles were calculated to demonstrate the internal structure and morphological transformation during the self-assembly process.Our findings indicate that the morphology of the internal solvophilic channels is greatly influenced by the copolymer structure,concentration,and interaction parameters between the different side chains.The simulation results are consistent with available experimental observations,which can offer theoretical insights into the self-assembly of AABCs.
基金financially supported by the National Key R&D Program of China(No.2022YFB3707300)the National Natural Science Foundation of China(Nos.22133002,22373089)the support from the Excellent Youth Foundation of Henan Scientific Committee(No.242300421032).
文摘A significant challenge in developing block copolymer photonic crystals is constructing low-symmetric ordered phases,which are essential for achieving a complete photonic band gap.Here,we propose a promising strategy to create low-symmetric ordered morphologies by incorporating shape-anisotropic rod-like side chains into block copolymers.Using dissipative particle dynamics simulations,we demonstrate that block copolymers with longer rod-like side chains can self-assemble into a hexagonally packed columnar phase characterized by a low-symmetric rectangular cross-section.Photonic band structure calculations reveal that this low-symmetric columnar phase can exhibit a complete photonic band gap,with the gap size dependent on the aspect ratio of the rectangular cross-sections of the columns.Our findings suggest an effective approach to constructing low-symmetric photonic crystals through the self-assembly of block copolymers with shape-anisotropic segments.
基金supported by the National Natural Science Foundation of China(Nos.52130307 and 5240031453).
文摘The design of low-cost and high-performance cyclic olefin copolymers remains challenging.Ethylene copolymers with dicyclopentadiene(DCPD)were prepared using Ph_(2)C(Cp)(Flu)ZrCl_(2)(Cat.1),rac-Et(Ind)_(2)ZrCl_(2)(Cat.2),Me_(2)C(Cp)(Flu)ZrCl_(2)(Cat.3)andMe_(2)Si(Ind)_(2)ZrCl_(2)(Cat.4)combined with[Ph_(3)C][B(C_(6)F_(5))_(4)]/iBu_(3)Al.Ni(acac)_(2)/iBu_(3)Al was then used to catalyze the hydrogenation of the intracyclic double bonds of ethylene/DCPD copolymers.The results showed that compared to C_(2) symmetric catalysts(Cat.2 and Cat.4),Cs symmetric catalysts(Cat.1 and Cat.3)facilitated the incorporation of copolymers with higher DCPD.1H-and ^(13)C-NMR spectra indicated that ethylene/DCPD copolymerization occurred via enhancement of the norbornene ring.Additionally,measurement of the reactivity ratios provided further confirmation that the copolymers had random sequence distributions.All these samples demonstrated transmittance values above 90%in the visible wavelength range from 400 nm to 800 nm.By changing the fraction of monomers,the glass transition temperature,refractive index,Young's modulus,and tensile strength of the copolymer increased as the incorporation of DCPD increased,whereas the Abbe number and elongation at break decreased.Compared with ethylene/norbornene and ethylene/tetracyclicdodecene copolymers,ethylene/DCPD copolymers,with excellent optical and mechanical properties,are promising materials.
基金supported by the Fundamental Research Funds for the Central Universities(No.2024JBZX029)Shijiazhuang High Level Science and Technology Innovation and Entrepreneurship Talent Project(No.08202307)the National Natural Science Foundation of China(NSFC)(No.22173004).
文摘The optimization of polymer structures aims to determine an optimal sequence or topology that achieves a given target property or structural performance.This inverse design problem involves searching within a vast combinatorial phase space defined by components,se-quences,and topologies,and is often computationally intractable due to its NP-hard nature.At the core of this challenge lies the need to evalu-ate complex correlations among structural variables,a classical problem in both statistical physics and combinatorial optimization.To address this,we adopt a mean-field approach that decouples direct variable-variable interactions into effective interactions between each variable and an auxiliary field.The simulated bifurcation(SB)algorithm is employed as a mean-field-based optimization framework.It constructs a Hamiltonian dynamical system by introducing generalized momentum fields,enabling efficient decoupling and dynamic evolution of strongly coupled struc-tural variables.Using the sequence optimization of a linear copolymer adsorbing on a solid surface as a case study,we demonstrate the applica-bility of the SB algorithm to high-dimensional,non-differentiable combinatorial optimization problems.Our results show that SB can efficiently discover polymer sequences with excellent adsorption performance within a reasonable computational time.Furthermore,it exhibits robust con-vergence and high parallel scalability across large design spaces.The approach developed in this work offers a new computational pathway for polymer structure optimization.It also lays a theoretical foundation for future extensions to topological design problems,such as optimizing the number and placement of side chains,as well as the co-optimization of sequence and topology.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.22173051,21829301,21774066)College Discipline Innovation and Intelligence Introduction Program(111 Project(B16027)+1 种基金the International Cooperation Base(2016D01025)Tianjin International Joint Research and Development Center。
文摘Spatial confinement of block copolymers can induce frustrations,which can further be utilized to regulate self-assembled structures,thus providing an efficient route for fabricating novel structures.We studied the self-assembly of AB di-block copolymers(di-BCPs)confined in Janus spherical nanocavities using simulations,and explained the structure formation mechanisms.In the case of a strongly selective cavity wall,all the lamella-forming,gyroid-forming,and cylinder-forming di-BCPs can form interfacial frustration-induced Janus concentric perforated lamellar nanoparticles,whose outermost is a Janus spherical shell and the internal is a sphere with concentric perforated lamellar structure.In particular,Janus concentric perforated lamellar nanoparticles with holes distributed only near the equatorial plane were obtained in both lamella-forming and gyroid-forming di-BCPs,directly reflecting the effect of interfacial frustration.The minority-block domain of the cylider-forming di-BCPs may form hemispherical perforated lamellar structures with holes distributed in parallel layers with a specific orientation.For symmetric di-BCPs,both the A and B domains in each nanoparticle are continuous,interchangeable,and have rotational symmetry.While for gyroid-forming and cylinder-forming di-BCPs,only the majority-block domains are continuous in each nanoparticle,and holes in the minority-block domains usually have rotational symmetry.In the case of a weakly selective cavity wall,the inhomogeneity of the cavity wall results in structures having a specific orientation(such as flower-like and branched structures in gyroid-forming and cylinder-forming di-BCPs)and a perforated wetting layer with uniformly distributed holes.The novel nanoparticles obtained may have potential applications in nanotechnology as functional nanostructures or nanoparticles.
基金financially supported by the National Key R&D Program of China(No.2021YFB3801901)the Institutional Research Fund from Sichuan University(No.2020SCUNL205)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Higher Education Discipline Innovation Project(No.B20001)。
文摘Polymers that exhibit both biodegradability and chemical recyclability offer a promising solution to environmental pollution and resource scarcity. Poly(glycolic acid)(PGA) is a promising chemically recyclable polymer, characterized by its seawater degradability and high mechanical strength. In this study, aliphatic polycarbonates were synthesized through melt polycondensation and subsequently copolymerized with glycolide(GL) to produce chemically recyclable PGA based triblock copolymers with well-defined structures. The properties of these copolymers, including their thermal properties, crystallization behavior, and mechanical performance, can be effectively adjusted by modifying the structure and content of the middle block. Furthermore, an in-depth investigation reveals that the pyrolysis process involves ester exchange, radical, and back-biting reactions. In addition, the high-efficiency "Monomer↔Copolymer" chemical recycling loop has been established, achieving a remarkable yield exceeding 88% along with a purity greater than 99%.
基金financially supported by the National Natural Science Foundation of China(No.22071176)。
文摘Cutting-edge research has primarily focused on flow synthesis of linear block copolymers,lacking the ability for manipulating chain architectures for more extensive applications.Herein,we develop a flow chemistry platform for the continuous microflow synthesis of bottlebrush block copolymers(BBCPs)using a grafting-through method.This involves performing ring-opening metathesis polymerization(ROMP)of two different macromonomers within two microfluidic reactors connected in series.The microflow environment allows for complete monomer conversion within a few tens of seconds,benefiting from the superior mixing efficiency achieved in Z-shaped channels as indicated by both theoretical simulations and experimental results.Consequently,a library of well-defined BBCPs of up to 528 distinct samples can be produced within one day through automation of the continuous procedure,while keeping precise control on degree of polymerization(DP<4)and polydispersity indices(PDI<1.2).The synthetic method is generally applicable to different macromonomers with different compositions and contour lengths,yielding libraries of branched block copolymers with great diversity in physiochemical properties and chain architectures.This work presents a powerful platform for high-throughput production of branched copolymers,significantly lowering the costs of the materials for real applications.
基金supported by the National Natural Science Foundation of China (Grant Nos.U20A20168 and 62404120)the National Key R&D Program (Grant No.2022YFB3204100)+2 种基金the Postdoctoral Fellowship Program of CPSF (Grant Nos.GZB20240335 and GZC20231216)the China Postdoctoral Science Foundation (Grant No.2025T180151)the Initiative Scientific Research Program of the School of Integrated Circuits,Tsinghua University。
文摘Block copolymer(BCP) nanolithography offers potential beyond traditional photolithographic limits, yet reliably producing low-defect, perpendicular domains remains challenging. We introduce a microenvironmentdriven isothermal annealing method for directed self-assembly of BCP thin films. By annealing films at stable temperature in a quasi-sealed, inert-gas chamber, our approach promotes highly uniform perpendicular lamellar nanopatterns over large areas, effectively mitigating environmental fluctuations and emulating solvent-vapor annealing without solvent exposure. Resulting BCP structures demonstrate enhanced spatial coherence and notably low defect density. Furthermore, we successfully transfer these nanopatterns into precise metal nano-line arrays,confirming the method's capability for high-fidelity pattern replication. This scalable, solvent-free technique provides a robust, reliable route for high-resolution nanopatterning in advanced semiconductor manufacturing.
基金National Natural Science Foundation of China (No.29836130)
文摘Diblock copolymer poly(ethylene glycol) methyl ether–polylactide (MePEG–PLA) micelles were prepared by dialysis against water. Indomethacin (IMC) as a model drug was entrapped into the micelles by dialysis method. The critical micelle concentration (CMC) of the prepared micelles in distilled water investigated by fluorescence spectroscopy was 0.0051 mg/mL which is lower than that of common low molecular weight surfactants. The diameters of MePEGPLA micelles and IMC loaded MePEGPLA micelles in a number-averaged scale measured by dynamic light scattering were 52.4 and 53.7 nm respectively. The observation with transmission electron microscope and scanning electron microscope showed that the appearance of MePEGPLA micelles was in a spherical shape. The content of IMC incorporated in the core portion of the micelles was 18% (ω). The effects of the synthesis method of the copolymer on the polydispersity of the micelles and the yield of the micelles formation were discussed.
基金National Natural Science Foundation of Guangdong Province (020885,980504).
文摘Aim Ciprofloxacin polylactic acid microspheres (CFX-PLA-MS) were preparedusing solvent evaporation method from a solid-in-oil-in-water emulsion system. Methods Orthogonalexperiment was used to optimize the method of CFX-PLA-MS preparation. Microspheres werecharacterized in terms of morphology, size, encapsulation efficiency, drug loading and in vitro drugrelease. Results The physical state of CFX-PLA-MS was determined by scanning electron microscopy(SEM) and differential scanning calorimetry (DSC) . Microspheres formed were spherical with smoothsurfaces. Drug was enveloped in microspheres without mixing physically with PLA. The averageparticle size was 280.80 ± 0.15 μm, with over 90% of microspheres falling in the range of 250 -390 μm. The encapsulation efficiency was 65.8% ± 0.58% and the drug loading was 34.1% ± 0.51% .In vitro release study revealed a profile of sustained release of Ciprofloxacin from CFX-PLA-MS. Theaccumulated release percentage and half-life (T_(1/2) of Ciprofloxacin microspheres were 84.0% in53.2 h, and 31.9 h, respectively. Higuchi equation was Q= -0.0043 + 0.003 9 t^(1/2), r = 0.9941.Conclusion Ciprofloxacin microspheres have been successfully prepared and sustained release of CFXfrom microspheres is achieved.
