Microfibrillated cellulose(MFC)was functionalised using a reactive ionic liquid monomer,i.e.,glycidyltriethylammonium chloride(GTEAC),via chain-growth polymerisation,resulting in a novel cationic polyelectrolyte-graft...Microfibrillated cellulose(MFC)was functionalised using a reactive ionic liquid monomer,i.e.,glycidyltriethylammonium chloride(GTEAC),via chain-growth polymerisation,resulting in a novel cationic polyelectrolyte-grafted quaternised MFC(QMFC).The degree of quaternisation and maximum ion exchange capacity of the resulting QMFC were 2.13 mmol/g(i.e.,132 mg/g)and 1.51 mmol/g(i.e.,94 mg/g),respectively.Small-angle X-ray scattering(SAXS)and wide-angle X-ray scattering(WAXS)experiments confirmed the retention of monoclinic crystalline structure for cellulose I with the corresponding decrease in the degree of crystallinity from 85%to 56%and the increase in the spacing between cellulose crystallites by 35%.The presence of the amorphous and grafted polymers was confirmed by microscopy,thermal analysis,and water sorption exper-iments.QMFC filter cartridges were prepared and tested under dynamic flow conditions with a pressure of 0.2 MPa(retention time of 0.5 min).These cationic polyelectrolytes enhanced multi-site ion exchange interactions as evidenced by the Freundlich sorption isotherm.The QMFC filter cartridges demonstrated high anion removal efficiency values of 83.2%,98.1%,and 94.9%for NO_(3)^(−),SO_(4)^(2−),and PO_(4)^(3−),respectively.This system achieved a process mass efficiency of 2.79,an E-factor of 1.97,and an energy efficiency score of 66.3,which conforms to the green chemistry principles and demonstrates high potential for sustainable water purification.展开更多
Two-photon polymerisation lithography enables the three-dimensional(3D)-printing of high-resolution micron-and nano-scale structures.Structures that are 3D-printed using proprietary resins are transparent and are suit...Two-photon polymerisation lithography enables the three-dimensional(3D)-printing of high-resolution micron-and nano-scale structures.Structures that are 3D-printed using proprietary resins are transparent and are suitable as optical components.However,achieving a mix of opaque and transparent structures in a single optical component is challenging and requires multiple material systems or the manual introduction of ink after fabrication.In this study,we investigated an overexposure printing process for laser decomposition,which typically produces uncontrollable and random‘burnt’structures.Specifically,we present a printing strategy to control this decomposition process,realising the on-demand printing of opaque or transparent structures in a single lithographic step using a single resin.Using this method,opaque structures can be printed with a minimum feature size of approximately 10μm,which exhibit<15%transmittance at a thickness of approximately 30μm.We applied this process to print an opaque aperture integrated with a transparent lens to demonstrate an improved imaging contrast.展开更多
To achieve optimal recovery and value-added utilisation of cellulose in peanut shells,the cellulose in peanut shells was first extracted using the sodium hydroxide-sodium chlorite method.Then,cellulose hydrogel was pr...To achieve optimal recovery and value-added utilisation of cellulose in peanut shells,the cellulose in peanut shells was first extracted using the sodium hydroxide-sodium chlorite method.Then,cellulose hydrogel was prepared by graft copolymerisation using N,N’-methylenebisacrylamide as the cross-linking agent,sodium persulfate as the initiator,and acrylic acid as the monomer.Orthogonal optimisation experiments were designed to obtain optimal process parameters for hydrogel preparation with the cellulose dosage of 0.40 g,initiator dosage of 0.20 g,polymerisation temperature of 70°C,cross-linking agent of 0.25 g,and monomer dosage of 3.0 mL.The effect of initiator dosage on hydrogel synthesis was the most significant,followed by monomer dosage and reaction temperature.Characterisation using X-ray diffraction analysis and scanning electron microscopy revealed that the hydrogel was amorphous and exhibited a distinct three-dimensional double network structure.Hydrogel swelling kinetic analysis showed that the hydrogel swelling process was divided into three stages,and fitted the Schott secondary swelling kinetic model.The prepared hydrogel had a good adsorption effect on methylene blue;the adsorption of methylene blue by the hydrogel was 1.259 mg/g at 25°C when the initial concentration of methylene blue was 5 mg/L.The adsorption kinetics of the hydrogel fit the pseudo-first-order kinetic model,pseudo-secondorder kinetic model,Eovich model and particle diffusion model.The best fitting effect was obtained with the pseudo-second-order kinetic model.The adsorption isotherm analysis of methylene blue on hydrogel showed that the adsorption process was consistent with Langmuir and Freundlich models.The correlation coefficient of the Freundlich isotherm model was higher,indicating that the adsorption of methylene blue on hydrogel was mainly chemisorption.展开更多
Fe2O3@polypyrrole nanotubes （Fe2O3@PPy nanotubes） have been successfully prepared by in-situ polymerization of the pyrrole on the surface of Fe2O3 nanotubes （Fe2O3-NTs）, via using L-Lysine as modified surfactant. ...Fe2O3@polypyrrole nanotubes （Fe2O3@PPy nanotubes） have been successfully prepared by in-situ polymerization of the pyrrole on the surface of Fe2O3 nanotubes （Fe2O3-NTs）, via using L-Lysine as modified surfactant. Hollow PPy nanotubes were also produced by dissolution of the Fe2O3 core from the core/shell composite nanotubes with 1 mol,L-1 HC1. Scanning electron microscopy（SEM）, transmission electron microscope （TEM）, selective-area electron diffraction （SAED）, X-ray powder diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and Fourier transform infrared spectroscopy（FT-IR） confirmed the formation of Fe2O3-NTs and Fe2O3@PPy core/shell nanotubes. Its catalytic properties were investigated under the ultrasound. The results of UV-vis spectroscopy （UV） demonstrated Rhodamine B （RhB） can be efficiently degraded by Fe2O3 @PPy nanotubes.展开更多
The present study investigates the effect of a silver (Ag)-containing nanocomposite coating on Staphylococcus epidermidis adhesion and icaA gene expression. Bacterial interactions with organic coatings with and withou...The present study investigates the effect of a silver (Ag)-containing nanocomposite coating on Staphylococcus epidermidis adhesion and icaA gene expression. Bacterial interactions with organic coatings with and without Ag nanoclusters were assessed through a combination of both conventional phenotypic analysis, using microscopy, and genotypic analysis, using the relative reverse transcription Real-Time Polymerase Chain Reaction (RT-PCR). The results suggest that the incorporation of Ag in organic coatings can significantly decrease bacterial adhesion and viability with time, in comparison to the organic coating alone. The initial Ag release though at concentrations lower than the bactericidal, significantly increased icaA gene expression for the bacteria interacting with the Ag containing coating two hours post adhesion, especially under the higher shear rate. Stress-inducing conditions such as sub-bactericidal concentrations of Ag and high shear rate can therefore increase icaA expression, indicating that analysis of gene expression can not only refine our knowledge of bacterial-material interactions, but also yield novel biomarkers for potential use in assessing biomaterials antimicrobial performance.展开更多
Introduction Calixarenes are versatile host molecules for molecular recognition and supramolecular assembly because its functional groups can be readily introduced into the phenolic OH or the para position to realize...Introduction Calixarenes are versatile host molecules for molecular recognition and supramolecular assembly because its functional groups can be readily introduced into the phenolic OH or the para position to realize a wide variety of functions calixarenes-based polymers tion as these polymers can During the past decade, received increasing attenbe used to synthesize the materials that are suitable for the preparation of chemical sensor devices such as ion-selective electrodes or transport membranes.展开更多
Selective semihydrogenation of acetylene to ethylene is an industrially critical purification step[1].In petrochemical plants,trace acetylene(<<1 vol%)must be removed from cracker-derived ethylene to protect dow...Selective semihydrogenation of acetylene to ethylene is an industrially critical purification step[1].In petrochemical plants,trace acetylene(<<1 vol%)must be removed from cracker-derived ethylene to protect downstream ZieglerNatta polymerisation catalysts and ensure product quality.展开更多
Laser direct writing employing multi-photon 3D polymerisation is a scientific and industrial tool used in various fields such as micro-optics,medicine,metamaterials,programmable materials,etc.,due to the fusion of hig...Laser direct writing employing multi-photon 3D polymerisation is a scientific and industrial tool used in various fields such as micro-optics,medicine,metamaterials,programmable materials,etc.,due to the fusion of highthroughput and fine features down to hundreds of nm.Some limitations of technology applicability emerge from photo-resin properties,however any material modifications can strongly affect its printability,as photoexcitation conditions alter as well.Here we present wavelength-independent 3D polymerisation using low peak power laser oscillators.High pulse repetition rate and fast laser direct writing was employed for advancing additive manufacturing out of the SZ2080^(TM)photo-resist without any photo-initiator.Wavelengths of 517 nm,780 nm,and 1035 nm are shown to be suitable for producing 300 nm polymerized features even at high-up to 10^(5)μm/s-writing speeds.Variation of organic-inorganic ratio in hybrid material results in shift and decrease of the dynamic fabrication window,yet not prohibiting the photo-structuring.Controlled energy deposition per focal volume is achieved due to localized heating enabling efficient 3D printing.Such spatio-selective photo-chemical crosslinking widens optical manufacturing capacity of non-photo-sensitive materials.展开更多
Nanofibre-supported forward osmosis(FO)membranes have gained popularity owing to their low structural parameters and high water flux.However,the nanofibrous membranes are less stable in long-term use,and their fouling...Nanofibre-supported forward osmosis(FO)membranes have gained popularity owing to their low structural parameters and high water flux.However,the nanofibrous membranes are less stable in long-term use,and their fouling behaviours with foulants in both feed solution(FS)and draw solution(DS)is less studied.This study developed a nanofibrous thin-film composite(TFC)FO membrane by designing a tiered dual-layer nanofibrous substrate to enhance membrane stability during long-term usage and cleaning.Various characterisation methods were used to study the effect of the electrospun nanofibre interlayer and drying time,which is the interval after removing the M-phenylenediamine(MPD)solution and before reacting with trimesoyl chloride(TMC)solution,on the intrinsic separation FO performance.The separation performance of the dual-layer nanofibrous FO membranes was examined using model foulants(sodium alginate and bovine serum albumin)in both the FS and DS.The dual-layer nanofibrous substrate was superior to the single-layer nanofibrous substrate and showed a flux of 30.2 L/m^(2)/h(LMH)when using 1.5 mol/L NaCl against deionised(DI)water in the active layer facing draw solution(AL-DS)mode.In the fouling test,the water flux was effectively improved without sacrificing the water/solute selectivity under the condition that foulants existed in both the FS and DS.In addition,the dual-layer nanofibrous TFC FO membrane was more robust during the fouling test and cleaning.展开更多
基金support received from the Deutscher Akademische Austauchsdienst(DAAD)in the form of the Short-term Research(No.57693450)that partially funded his research stay at the time of this research.
文摘Microfibrillated cellulose(MFC)was functionalised using a reactive ionic liquid monomer,i.e.,glycidyltriethylammonium chloride(GTEAC),via chain-growth polymerisation,resulting in a novel cationic polyelectrolyte-grafted quaternised MFC(QMFC).The degree of quaternisation and maximum ion exchange capacity of the resulting QMFC were 2.13 mmol/g(i.e.,132 mg/g)and 1.51 mmol/g(i.e.,94 mg/g),respectively.Small-angle X-ray scattering(SAXS)and wide-angle X-ray scattering(WAXS)experiments confirmed the retention of monoclinic crystalline structure for cellulose I with the corresponding decrease in the degree of crystallinity from 85%to 56%and the increase in the spacing between cellulose crystallites by 35%.The presence of the amorphous and grafted polymers was confirmed by microscopy,thermal analysis,and water sorption exper-iments.QMFC filter cartridges were prepared and tested under dynamic flow conditions with a pressure of 0.2 MPa(retention time of 0.5 min).These cationic polyelectrolytes enhanced multi-site ion exchange interactions as evidenced by the Freundlich sorption isotherm.The QMFC filter cartridges demonstrated high anion removal efficiency values of 83.2%,98.1%,and 94.9%for NO_(3)^(−),SO_(4)^(2−),and PO_(4)^(3−),respectively.This system achieved a process mass efficiency of 2.79,an E-factor of 1.97,and an energy efficiency score of 66.3,which conforms to the green chemistry principles and demonstrates high potential for sustainable water purification.
基金funded by the Singapore University of Technology and Design(SUTD)through the SUTD Ph.D.Fellowship.
文摘Two-photon polymerisation lithography enables the three-dimensional(3D)-printing of high-resolution micron-and nano-scale structures.Structures that are 3D-printed using proprietary resins are transparent and are suitable as optical components.However,achieving a mix of opaque and transparent structures in a single optical component is challenging and requires multiple material systems or the manual introduction of ink after fabrication.In this study,we investigated an overexposure printing process for laser decomposition,which typically produces uncontrollable and random‘burnt’structures.Specifically,we present a printing strategy to control this decomposition process,realising the on-demand printing of opaque or transparent structures in a single lithographic step using a single resin.Using this method,opaque structures can be printed with a minimum feature size of approximately 10μm,which exhibit<15%transmittance at a thickness of approximately 30μm.We applied this process to print an opaque aperture integrated with a transparent lens to demonstrate an improved imaging contrast.
基金This study was supported by the National Visiting Scholar Program for Key Young Teachers of Central and Western Universities,the Ministry of Education(19042)the Key Science and Technology Project of Henan Province(212102310064)the National Innovation and Entrepreneurship Training Program for College Students,Ministry of Education(202111517002).
文摘To achieve optimal recovery and value-added utilisation of cellulose in peanut shells,the cellulose in peanut shells was first extracted using the sodium hydroxide-sodium chlorite method.Then,cellulose hydrogel was prepared by graft copolymerisation using N,N’-methylenebisacrylamide as the cross-linking agent,sodium persulfate as the initiator,and acrylic acid as the monomer.Orthogonal optimisation experiments were designed to obtain optimal process parameters for hydrogel preparation with the cellulose dosage of 0.40 g,initiator dosage of 0.20 g,polymerisation temperature of 70°C,cross-linking agent of 0.25 g,and monomer dosage of 3.0 mL.The effect of initiator dosage on hydrogel synthesis was the most significant,followed by monomer dosage and reaction temperature.Characterisation using X-ray diffraction analysis and scanning electron microscopy revealed that the hydrogel was amorphous and exhibited a distinct three-dimensional double network structure.Hydrogel swelling kinetic analysis showed that the hydrogel swelling process was divided into three stages,and fitted the Schott secondary swelling kinetic model.The prepared hydrogel had a good adsorption effect on methylene blue;the adsorption of methylene blue by the hydrogel was 1.259 mg/g at 25°C when the initial concentration of methylene blue was 5 mg/L.The adsorption kinetics of the hydrogel fit the pseudo-first-order kinetic model,pseudo-secondorder kinetic model,Eovich model and particle diffusion model.The best fitting effect was obtained with the pseudo-second-order kinetic model.The adsorption isotherm analysis of methylene blue on hydrogel showed that the adsorption process was consistent with Langmuir and Freundlich models.The correlation coefficient of the Freundlich isotherm model was higher,indicating that the adsorption of methylene blue on hydrogel was mainly chemisorption.
文摘Fe2O3@polypyrrole nanotubes （Fe2O3@PPy nanotubes） have been successfully prepared by in-situ polymerization of the pyrrole on the surface of Fe2O3 nanotubes （Fe2O3-NTs）, via using L-Lysine as modified surfactant. Hollow PPy nanotubes were also produced by dissolution of the Fe2O3 core from the core/shell composite nanotubes with 1 mol,L-1 HC1. Scanning electron microscopy（SEM）, transmission electron microscope （TEM）, selective-area electron diffraction （SAED）, X-ray powder diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and Fourier transform infrared spectroscopy（FT-IR） confirmed the formation of Fe2O3-NTs and Fe2O3@PPy core/shell nanotubes. Its catalytic properties were investigated under the ultrasound. The results of UV-vis spectroscopy （UV） demonstrated Rhodamine B （RhB） can be efficiently degraded by Fe2O3 @PPy nanotubes.
文摘The present study investigates the effect of a silver (Ag)-containing nanocomposite coating on Staphylococcus epidermidis adhesion and icaA gene expression. Bacterial interactions with organic coatings with and without Ag nanoclusters were assessed through a combination of both conventional phenotypic analysis, using microscopy, and genotypic analysis, using the relative reverse transcription Real-Time Polymerase Chain Reaction (RT-PCR). The results suggest that the incorporation of Ag in organic coatings can significantly decrease bacterial adhesion and viability with time, in comparison to the organic coating alone. The initial Ag release though at concentrations lower than the bactericidal, significantly increased icaA gene expression for the bacteria interacting with the Ag containing coating two hours post adhesion, especially under the higher shear rate. Stress-inducing conditions such as sub-bactericidal concentrations of Ag and high shear rate can therefore increase icaA expression, indicating that analysis of gene expression can not only refine our knowledge of bacterial-material interactions, but also yield novel biomarkers for potential use in assessing biomaterials antimicrobial performance.
基金the National Natural Science Foundation of China(No 29971023)
文摘Introduction Calixarenes are versatile host molecules for molecular recognition and supramolecular assembly because its functional groups can be readily introduced into the phenolic OH or the para position to realize a wide variety of functions calixarenes-based polymers tion as these polymers can During the past decade, received increasing attenbe used to synthesize the materials that are suitable for the preparation of chemical sensor devices such as ion-selective electrodes or transport membranes.
文摘Selective semihydrogenation of acetylene to ethylene is an industrially critical purification step[1].In petrochemical plants,trace acetylene(<<1 vol%)must be removed from cracker-derived ethylene to protect downstream ZieglerNatta polymerisation catalysts and ensure product quality.
基金funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101007417having benefited from the access provided by FORTH in Two-photon Lithography(TWL),Scanning Electron Microscopy(SEM),PhotoLuminescence(PL)within the framework of the NFFA-Europe Pilot Transnational Access Activity,proposal[ID-077].The research leading to these results has received funding from LASERLAB-EUROPE(grant agreement no.871124,European Union’s Horizon 2020 research and innovation programme)+2 种基金A.B.,E.S.and M.M acknowledge Vilnius University Excellence Initiative programme,and S.J.under Adjunct agreement as Visiting Professor for mutual research activities with the Laser Research Center of the Faculty of Physics of Vilnius UniversityFurthermore,part of this work was co-financed by Greece and the European Union(European Social Fund-ESF)through the Operational Programme“Human Resources Development,Education and Lifelong Learning”in the context of the Act“Enhancing Human Resources Research Potential by undertaking a Doctoral Research”Sub-action 2:IKY Scholarship Programme for Ph.D.candidates in the Greek UniversitiesThe research project was co-funded by the Stavros Niarchos Foundation(SNF)and the Hellenic Foundation for Research and Innovation(H.F.R.I.)under the 5th Call of“Science and Society”Action-“Always Strive for Excellence-Theodore Papazoglou”(Project Number:9578.)。
文摘Laser direct writing employing multi-photon 3D polymerisation is a scientific and industrial tool used in various fields such as micro-optics,medicine,metamaterials,programmable materials,etc.,due to the fusion of highthroughput and fine features down to hundreds of nm.Some limitations of technology applicability emerge from photo-resin properties,however any material modifications can strongly affect its printability,as photoexcitation conditions alter as well.Here we present wavelength-independent 3D polymerisation using low peak power laser oscillators.High pulse repetition rate and fast laser direct writing was employed for advancing additive manufacturing out of the SZ2080^(TM)photo-resist without any photo-initiator.Wavelengths of 517 nm,780 nm,and 1035 nm are shown to be suitable for producing 300 nm polymerized features even at high-up to 10^(5)μm/s-writing speeds.Variation of organic-inorganic ratio in hybrid material results in shift and decrease of the dynamic fabrication window,yet not prohibiting the photo-structuring.Controlled energy deposition per focal volume is achieved due to localized heating enabling efficient 3D printing.Such spatio-selective photo-chemical crosslinking widens optical manufacturing capacity of non-photo-sensitive materials.
基金the National Natural Science Foundation of China(No.52100105)the Natural Science Foundation of Shaanxi Province(China)(No.2021JQ-108).
文摘Nanofibre-supported forward osmosis(FO)membranes have gained popularity owing to their low structural parameters and high water flux.However,the nanofibrous membranes are less stable in long-term use,and their fouling behaviours with foulants in both feed solution(FS)and draw solution(DS)is less studied.This study developed a nanofibrous thin-film composite(TFC)FO membrane by designing a tiered dual-layer nanofibrous substrate to enhance membrane stability during long-term usage and cleaning.Various characterisation methods were used to study the effect of the electrospun nanofibre interlayer and drying time,which is the interval after removing the M-phenylenediamine(MPD)solution and before reacting with trimesoyl chloride(TMC)solution,on the intrinsic separation FO performance.The separation performance of the dual-layer nanofibrous FO membranes was examined using model foulants(sodium alginate and bovine serum albumin)in both the FS and DS.The dual-layer nanofibrous substrate was superior to the single-layer nanofibrous substrate and showed a flux of 30.2 L/m^(2)/h(LMH)when using 1.5 mol/L NaCl against deionised(DI)water in the active layer facing draw solution(AL-DS)mode.In the fouling test,the water flux was effectively improved without sacrificing the water/solute selectivity under the condition that foulants existed in both the FS and DS.In addition,the dual-layer nanofibrous TFC FO membrane was more robust during the fouling test and cleaning.
