To unlock the full potential of PSCs,machine learning(ML)was implemented in this research to predict the optimal combination of mesoporous-titanium dioxide(mp-TiO_(2))and weight percentage(wt%)of phenyl-C_(61)-butyric...To unlock the full potential of PSCs,machine learning(ML)was implemented in this research to predict the optimal combination of mesoporous-titanium dioxide(mp-TiO_(2))and weight percentage(wt%)of phenyl-C_(61)-butyric acid methyl ester(PCBM),along with the current density(J_(sc)),open-circuit voltage(V_(oc)),fill factor(ff),and energy conversion efficiency(ECE).Then,the combination that yielded the highest predicted ECE was selected as a reference to fabricate PCBM-PSCs with nanopatterned TiO_(2)layer.Subsequently,the PCBM-PSCs with nanopatterned TiO_(2)layers were fabricated and characterized to further understand the effects of nanopatterning depth and wt%of PCBM on PSCs.Experimentally,the highest ECE of 17.338%is achieved at 127 nm nanopatterning depth and 0.10 wt%of PCBM,where the J_(sc),V_(oc),and ff are 22.877 mA cm^(-2),0.963 V,and 0.787,respectively.The measured J_(sc),V_(oc),ff,and ECE values show consistencies with the ML prediction.Hence,these findings not only revealed the potential of ML to be used as a preliminary investigation to navigate the research of PSCs but also highlighted that nanopatterning depth has a significant impact on J_(sc),and the incorporation of PCBM on perovskite layer influenced the V_(oc)and ff,which further boosted the performance of PSCs.展开更多
Bacterial adhesion is a critical process in many fields,such as implant infections,microbiologically influenced corrosion and bioelectricity generation in microbial fuel cells.During bacterial adhesion,the contact are...Bacterial adhesion is a critical process in many fields,such as implant infections,microbiologically influenced corrosion and bioelectricity generation in microbial fuel cells.During bacterial adhesion,the contact area between the attached bacteria and the patterned surface plays an important role.In this study,different surface topographies and treatments were employed to simulate three circumstances with different contact areas.A nanostripe structure with a period of 576.9 nm and a height of 203.5 nm was fabricated on pure titanium by femtosecond laser ablation.Bacteria in liquid attached to the peaks of the nanostripe structure and were stretched on the two adjacent nanostripes.Compared with the polished surface,the contact area between bacteria and the nanostripe surface was reduced to 50%,resulting in a reduction(about 50%)in the coverage rate of attached bacteria.In addition,the nanostripe surface was a hydrophobic surface with a water contact angle(WCA)of 112.1°,and the surface potential of the nanostripe surface was higher than that of the polished surface.However,the surface potential and wettability of the nanostripe surface played a minor role in the bacterial adhesion due to the reduced contact area.Upon drying,the attached bacteria on the nanostripe surface sank into the valley region and the contact area was about 40%larger than that on the polished surface.The lateral strength of bacterial adhesion on nanostripe surfaces was higher than that on polished surfaces,due to the larger contact area.Upon applying a lateral force of 10.0 nN,the percentage of bacteria remaining on the nanostripe surface(31.1%)was higher than that on the polished surface(11.9%).Hence,the bacterial adhesion on the nanopatterned surface was mainly determined by the contact area.The in-depth exploration of the relation between bacterial adhesion on the nanopatterned surface and the contact area enables the rational surface designs of biomaterials to regulate bacterial adhesion.展开更多
A novel two-dimensional nanopattemed TiO2 thin film has been synthesized through the interaction between cationic Gemini surfactant molecules and the prepared TiO2 colloid nanoparticles with average diameters of 8 nm ...A novel two-dimensional nanopattemed TiO2 thin film has been synthesized through the interaction between cationic Gemini surfactant molecules and the prepared TiO2 colloid nanoparticles with average diameters of 8 nm by controlling the surface pressure of the monolayer. TEM photographs from the formed Gemini-TiO2 composite monolayer confirm that the prepared TiO2 film is of a branch nanopattern.展开更多
As a well-known natural protein biomaterial,silk fibroin(SF)has shown broad application prospects in typical biomedical fields.However,the mostly used SF from Bombyx mori silkworm lacks specific cell adhesion sites an...As a well-known natural protein biomaterial,silk fibroin(SF)has shown broad application prospects in typical biomedical fields.However,the mostly used SF from Bombyx mori silkworm lacks specific cell adhesion sites and other bioactive peptide sequences,and there is still significant room for further improvement of their biological functions.Therefore,it is crucial to develop a facile and effective modification strategy for this widely researched biomaterial.In this study,the SF electrospun scaffold has been chosen as a typical SF biomaterial,and air plasma etching has been adopted as a facile nanopattern modification strategy to promote its biological functions.Results demonstrated that the plasma etching could feasibly and effectively create nano-island-like patterns on the complex surface of SF scaffolds,and the detailed nanopattern features could be easily regulated by adjusting the etching time.In addition,the mesenchymal stem cell responses have illustrated that the nanopattern modification could significantly regulate corresponding cell behaviors.Compared with the non-etched scaffold,the 10min-etched scaffolds(10E scaffold)significantly promoted stem cell proliferation and osteogenic differentiation.Moreover,10E scaffold has also been confirmed to effectively accelerate vascularization and ectopic osteogenesis in vivo using a rat subcutaneous implantation model.However,the mentioned promoting effects would be weakened or even counteracted with the increase of etching time.In conclusion,this facile modification strategy demonstrated great application potential for promoting cell proliferation and differentiation.Thus,it provided useful guidance to develop excellent SF-based scaffolds suitable for bone and other tissue engineering.展开更多
Nanoparticles monolayer formation by spin coating is considered to be a simple, fast and inexpensive nanopatteming technique However, the parameters that govern the overall growth process in this technique are not com...Nanoparticles monolayer formation by spin coating is considered to be a simple, fast and inexpensive nanopatteming technique However, the parameters that govern the overall growth process in this technique are not completely quantified and techniques for the controlled and continuous growth of close packed monolayer particle arrays without defects need to be developed. In this paper, an ordered particle array formation process is analyzed theoretically, employing material flux balance and parti- cle-subjected forces balance, based on the film thickness model of spin coating and evaporation rate law. A series of experi- ments were conducted using silica particle suspensions with various particle volume fractions and different spin speeds. The results show that the spin speed should match the particle volume fraction to meet the requirements of material flux and particles movement in order to obtain a close packed monolayer film. The formation mechanism of fabrication defects involving particle agglomeration and uncontrollable voids were analyzed qualitatively based on crystal growth theory, and validation experiments were performed. The formation of highly uniform close-packed monolayer films was demonstrated and the condi- tion requirements for achieving monolayer nanoparticles array with good quality presented.展开更多
Three-dimensional(3D)nanoarchitectures have offered unprecedented material performances in diverse applications like energy storages,catalysts,electronic,mechanical,and photonic devices.These outstanding performances ...Three-dimensional(3D)nanoarchitectures have offered unprecedented material performances in diverse applications like energy storages,catalysts,electronic,mechanical,and photonic devices.These outstanding performances are attributed to unusual material properties at the nanoscale,enormous surface areas,a geometrical uniqueness,and comparable feature sizes with optical wavelengths.For the practical use of the unusual nanoscale properties,there have been developments for macroscale fabrications of the 3D nanoarchitectures with process areas over centimeter scales.Among the many fabrication methods for 3D structures at the nanoscale,proximity-field nanopatterning(PnP)is one of the promising techniques that generates 3D optical holographic images and transforms them into material structures through a lithographic process.Using conformal and transparent phase masks as a key factor,the PnP process has advantages in terms of stability,uniformity,and reproducibility for 3D nanostructures with periods from 300 nm to several micrometers.Other merits of realizing precise 3D features with sub-100 nm and rapid processes are attributed to the interference of coherent light diffracted by phase masks.In this review,to report the overall progress of PnP from 2003,we present a comprehensive understanding of PnP,including its brief history,the fundamental principles,symmetry control of 3D nanoarchitectures,material issues for the phase masks,and the process area expansion to the wafer-scale for the target applications.Finally,technical challenges and prospects are discussed for further development and practical applications of the PnP technique.展开更多
Functionalization of silicon substrate surfaces with a stable monolayer for resisting non-specific adsorption of proteins has attracted great interest,since it is directly relevant to the development of miniature,sili...Functionalization of silicon substrate surfaces with a stable monolayer for resisting non-specific adsorption of proteins has attracted great interest,since it is directly relevant to the development of miniature,silicon-based biosensors and implantable microdevices,such as silicon-neuron interfaces.This brief review summarizes our contribution to the development of robust monolayers grown by surface hydrosilylation on atomically flat,hydrogen-terminated silicon surfaces.The review also outlines our strategy and progress on the fabrication of single molecule patterns on such monolayer platforms.展开更多
We present measurements of the in situ, microscopic architecture of a self- assembled bilayer at the interface between a regularly nanopatterned surface and an aqueous sub-phase using neutron reflectometry. The substr...We present measurements of the in situ, microscopic architecture of a self- assembled bilayer at the interface between a regularly nanopatterned surface and an aqueous sub-phase using neutron reflectometry. The substrate is patterned with a rectangular array of nanoscale holes. Because of the high quality of the pattern, using neutron reflectometry, we are able to map the surface-normal density distribution of the patterned silicon, the penetration of water into the pattern, and the distribution of a deposited film inside and outside of the etched holes. In this stud; 1,2-dilauroyl-sn-glycero-3-phosphocholine （DLPC） single bilayers were deposited on the hydrophilic patterned surface. For bilayers deposited either by vesicle fusion （VF） or by the Langmuir-Schaefer （L-S） technique, the most consistent model found to fit the data shows that the lipids form bilayer coatings on top of the substrate as well as the bottoms of the holes in an essentially conformal fashion. However, while there is a single bilayer on the unetched silicon surface, the lipids coating the bottoms of the holes form a complex bimodal structure consistent with a rough surface produced by the etching process. This study provides insight into film transfer both outside and inside regular nanopatterned features.展开更多
Anisotropic nanopatterns have potentials in constructing novel plasmonic structures which have various applications in such as super-resolution microscopy, medicine, and sensors. However, it remains challenging to bui...Anisotropic nanopatterns have potentials in constructing novel plasmonic structures which have various applications in such as super-resolution microscopy, medicine, and sensors. However, it remains challenging to build big anisotropic nanopatterns that are suitable for big noble metal nanoparticles. Herein, we report a simple and reliable strategy for constructing DNA origami-based big anisotropic nanopatterns with controlled size and shape, nanoscale resolution, and fully addressability. Two kinds of basic DNA origami nanoblocks-cross-shaped and rectangular DNA origami units were used. We have demonstrated that by encoding nanoblocks' edges, anisotropic higher-order nanopatterns, such as dimer, trimer, tetramer and mini "windmill" like pentamer nanopatterns could be constructed. To show the potential use as template to direct the assembly of anisotropic nanoparticles arrays, a proof of concept work was conducted by anchoring streptavidin nanoparticles on the "windmill" template to form a chiral array. Significantly, these nanopatterns have the sizes of hundreds of nanometers, which are in principle also suitable for big noble metal nanoparticles arrays.展开更多
The development of nanoelectronics and nanotechnologies has been boosted significantly by the emergence of 2D materials because of their atomic thickness and peculiar properties,and developing a universal,precise patte...The development of nanoelectronics and nanotechnologies has been boosted significantly by the emergence of 2D materials because of their atomic thickness and peculiar properties,and developing a universal,precise patterning technology for single-layer 2D materials is critical for assembling nanodevices.Demonstrated here is a nanomachining technique using electrical breakdown by an AFM tip to fabricate nanopores,nanostrips,and other nanostructures on demand.This can be achieved by voltage scanning or applying a constant voltage while moving the tip.By measuring the electrical current,the formation process on single-layer materials was shown quantitatively.The present results provide evidence of successful pattern fabrication on single-layer MoS2,boron nitride,and graphene,although further confirmation is still needed.The proposed method holds promise as a general nanomachining technology for the future.展开更多
The morphology of linear polybutadiene physisorbed on freshly cleaved mica from a dilute polymer solution is investigated through atomic force microscopy.A fine-structure study shows that the monolayer morphology in a...The morphology of linear polybutadiene physisorbed on freshly cleaved mica from a dilute polymer solution is investigated through atomic force microscopy.A fine-structure study shows that the monolayer morphology in air(after rapid solvent evaporation)depends strongly on the molecular weight(Mw)of the linear polymer,the adsorbed amount,and the conformation adopted by the adsorbed polymer chains under good solvent conditions.The dependence of the observed polymer structure on Mw is most significant for samples with high surface density,where the intermolecular interactions among the adsorbed polymers are important.For high surface density,the adsorbed polymers tend to aggregate and minimize unfavorable contacts with air for all of the different Mw samples,leading to an isotropic structural pattern.These structural phenomena with increasing surface density are explained on the basis of the intermolecular interactions of the adsorbed polymers under good solvent conditions,and after the abrupt solvent evaporation corresponding to poor solvent conditions.The experimental observations are further discussed using the results obtained from molecular dynamics simulations of a simple coarse-grained model.展开更多
In this paper, microphase behavior of an ABC triblock copolymer, polystyrene-block-poly（2-vinylpyridine）-block- poly（ethylene oxide）, namely PS-b-P2VP-b-PEO, was systematically studied during spin-coating and solv...In this paper, microphase behavior of an ABC triblock copolymer, polystyrene-block-poly（2-vinylpyridine）-block- poly（ethylene oxide）, namely PS-b-P2VP-b-PEO, was systematically studied during spin-coating and solvent vapor annealing based on various parameters, including the types of the solvent, spin speed and thickness. The morphological features and the microdomain location of the different blocks were characterized by atomic force microscope （AFM） and high resolution transmission electron microscopy （HRTEM）. With increasing thickness, the order-order transition from nanopores array to the pattern of nanostripes was observed due to microdomain coarsening. These processes of pattern transformation were based on the selectivity of toluene for different blocks and on the contact time between solvent molecules and the three blocks. This work provides different templates for preparation of gold nanoparticle array on silicon wafer, which can be adopted as an active surface-enhanced Raman scattering （SERS） substrate for poly（3-hexylthiophene） （P3HT）.展开更多
A method is presented for nano-patterning a diffraction grating on human hair with a focused ion beam. Strands of brown hair are patterned with hyperbolas and Archimedean spirals whose pitches range from 540 nm to 104...A method is presented for nano-patterning a diffraction grating on human hair with a focused ion beam. Strands of brown hair are patterned with hyperbolas and Archimedean spirals whose pitches range from 540 nm to 1040 nm. Exposure of the hair strands to white light at various incident angles demonstrates that light of varying wavelengths is diffracted by the diffraction gratings. The diffraction causes the brown strands of hair to reflect light from the entire range of visible light.展开更多
The atomic edge structure of graphene governs its unique electronic properties with applications in nanoscale electronics and optoelectronics.To fully realize its potential,it is critical to develop a precision etchin...The atomic edge structure of graphene governs its unique electronic properties with applications in nanoscale electronics and optoelectronics.To fully realize its potential,it is critical to develop a precision etching process producing graphene edges along desired directions.Here,we present a novel approach utilizing scanning probe lithography(SPL)facilitated by a mechanochemical atomic attrition process.This technique enables the fabrication of nanopatterns in single-layer graphene from graphene edges,precisely along the crystallographic orientation of zigzag(ZZ)and armchair(AC)edges,without inducing mechanical damage to the surrounding area.Density functional theory(DFT)calculations revealed that the dissociation of CC bonds by the SPL probe is mediated by the formation of interfacial bridge bonds between the graphene edge and the reactive silica surface.This SPL-based mechanochemical etching method enables the construction of various nanodevice structures with specific edge orientations,which allows the exploitation of their electronic properties.展开更多
基金supported by the“Human Resources Program in Energy Technology”of the Korea Institute of Energy Technology Evaluation and Planning(KETEP),which received financial resources from the Ministry of Trade,Industry&Energy,Republic of Korea(No.20204010600470)the Korea Evaluation Institute of Industrial Technology(KEIT)and the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(No.20018608)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2022R1I1A1A01064236)
文摘To unlock the full potential of PSCs,machine learning(ML)was implemented in this research to predict the optimal combination of mesoporous-titanium dioxide(mp-TiO_(2))and weight percentage(wt%)of phenyl-C_(61)-butyric acid methyl ester(PCBM),along with the current density(J_(sc)),open-circuit voltage(V_(oc)),fill factor(ff),and energy conversion efficiency(ECE).Then,the combination that yielded the highest predicted ECE was selected as a reference to fabricate PCBM-PSCs with nanopatterned TiO_(2)layer.Subsequently,the PCBM-PSCs with nanopatterned TiO_(2)layers were fabricated and characterized to further understand the effects of nanopatterning depth and wt%of PCBM on PSCs.Experimentally,the highest ECE of 17.338%is achieved at 127 nm nanopatterning depth and 0.10 wt%of PCBM,where the J_(sc),V_(oc),and ff are 22.877 mA cm^(-2),0.963 V,and 0.787,respectively.The measured J_(sc),V_(oc),ff,and ECE values show consistencies with the ML prediction.Hence,these findings not only revealed the potential of ML to be used as a preliminary investigation to navigate the research of PSCs but also highlighted that nanopatterning depth has a significant impact on J_(sc),and the incorporation of PCBM on perovskite layer influenced the V_(oc)and ff,which further boosted the performance of PSCs.
基金financial support from the National Nat-ural Science Foundation of China(Nos.52071028 and 52003028)the Beijing Nova Program(2022 Beijing Nova Program Cross Coop-eration Program No.20220484178).
文摘Bacterial adhesion is a critical process in many fields,such as implant infections,microbiologically influenced corrosion and bioelectricity generation in microbial fuel cells.During bacterial adhesion,the contact area between the attached bacteria and the patterned surface plays an important role.In this study,different surface topographies and treatments were employed to simulate three circumstances with different contact areas.A nanostripe structure with a period of 576.9 nm and a height of 203.5 nm was fabricated on pure titanium by femtosecond laser ablation.Bacteria in liquid attached to the peaks of the nanostripe structure and were stretched on the two adjacent nanostripes.Compared with the polished surface,the contact area between bacteria and the nanostripe surface was reduced to 50%,resulting in a reduction(about 50%)in the coverage rate of attached bacteria.In addition,the nanostripe surface was a hydrophobic surface with a water contact angle(WCA)of 112.1°,and the surface potential of the nanostripe surface was higher than that of the polished surface.However,the surface potential and wettability of the nanostripe surface played a minor role in the bacterial adhesion due to the reduced contact area.Upon drying,the attached bacteria on the nanostripe surface sank into the valley region and the contact area was about 40%larger than that on the polished surface.The lateral strength of bacterial adhesion on nanostripe surfaces was higher than that on polished surfaces,due to the larger contact area.Upon applying a lateral force of 10.0 nN,the percentage of bacteria remaining on the nanostripe surface(31.1%)was higher than that on the polished surface(11.9%).Hence,the bacterial adhesion on the nanopatterned surface was mainly determined by the contact area.The in-depth exploration of the relation between bacterial adhesion on the nanopatterned surface and the contact area enables the rational surface designs of biomaterials to regulate bacterial adhesion.
基金supported by the National Natural Science Foundation of China(No.20473057)Shanghai Nanotechnology Promotion Center(No.0352nm094,No.0452nm088).
文摘A novel two-dimensional nanopattemed TiO2 thin film has been synthesized through the interaction between cationic Gemini surfactant molecules and the prepared TiO2 colloid nanoparticles with average diameters of 8 nm by controlling the surface pressure of the monolayer. TEM photographs from the formed Gemini-TiO2 composite monolayer confirm that the prepared TiO2 film is of a branch nanopattern.
基金supported by the International Cooperation Fund of the Science and Technology Commission of Shanghai Municipality(22520711900)National Natural Science Foundation of China(52273125,52173031)+2 种基金the Fundamental Research Funds for the Central Universities(2232024D-01)the Basic Research Project of the Science and Technology Commission of Shanghai Municipality(21JC1400100)the Oriental Talent Plan(Leading Talent Program,no.152).
文摘As a well-known natural protein biomaterial,silk fibroin(SF)has shown broad application prospects in typical biomedical fields.However,the mostly used SF from Bombyx mori silkworm lacks specific cell adhesion sites and other bioactive peptide sequences,and there is still significant room for further improvement of their biological functions.Therefore,it is crucial to develop a facile and effective modification strategy for this widely researched biomaterial.In this study,the SF electrospun scaffold has been chosen as a typical SF biomaterial,and air plasma etching has been adopted as a facile nanopattern modification strategy to promote its biological functions.Results demonstrated that the plasma etching could feasibly and effectively create nano-island-like patterns on the complex surface of SF scaffolds,and the detailed nanopattern features could be easily regulated by adjusting the etching time.In addition,the mesenchymal stem cell responses have illustrated that the nanopattern modification could significantly regulate corresponding cell behaviors.Compared with the non-etched scaffold,the 10min-etched scaffolds(10E scaffold)significantly promoted stem cell proliferation and osteogenic differentiation.Moreover,10E scaffold has also been confirmed to effectively accelerate vascularization and ectopic osteogenesis in vivo using a rat subcutaneous implantation model.However,the mentioned promoting effects would be weakened or even counteracted with the increase of etching time.In conclusion,this facile modification strategy demonstrated great application potential for promoting cell proliferation and differentiation.Thus,it provided useful guidance to develop excellent SF-based scaffolds suitable for bone and other tissue engineering.
基金supported by the National Natural Science Foundation of China(Grant Nos.51375381,51575427 and 51675422)the 2015 Overall Planning Innovation Project Foundation of Shaanxi Province(Grant No.2015KTCQ01-36)
文摘Nanoparticles monolayer formation by spin coating is considered to be a simple, fast and inexpensive nanopatteming technique However, the parameters that govern the overall growth process in this technique are not completely quantified and techniques for the controlled and continuous growth of close packed monolayer particle arrays without defects need to be developed. In this paper, an ordered particle array formation process is analyzed theoretically, employing material flux balance and parti- cle-subjected forces balance, based on the film thickness model of spin coating and evaporation rate law. A series of experi- ments were conducted using silica particle suspensions with various particle volume fractions and different spin speeds. The results show that the spin speed should match the particle volume fraction to meet the requirements of material flux and particles movement in order to obtain a close packed monolayer film. The formation mechanism of fabrication defects involving particle agglomeration and uncontrollable voids were analyzed qualitatively based on crystal growth theory, and validation experiments were performed. The formation of highly uniform close-packed monolayer films was demonstrated and the condi- tion requirements for achieving monolayer nanoparticles array with good quality presented.
基金supported by Creative Materials Discovery Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(No.2020M3D1A1110522).
文摘Three-dimensional(3D)nanoarchitectures have offered unprecedented material performances in diverse applications like energy storages,catalysts,electronic,mechanical,and photonic devices.These outstanding performances are attributed to unusual material properties at the nanoscale,enormous surface areas,a geometrical uniqueness,and comparable feature sizes with optical wavelengths.For the practical use of the unusual nanoscale properties,there have been developments for macroscale fabrications of the 3D nanoarchitectures with process areas over centimeter scales.Among the many fabrication methods for 3D structures at the nanoscale,proximity-field nanopatterning(PnP)is one of the promising techniques that generates 3D optical holographic images and transforms them into material structures through a lithographic process.Using conformal and transparent phase masks as a key factor,the PnP process has advantages in terms of stability,uniformity,and reproducibility for 3D nanostructures with periods from 300 nm to several micrometers.Other merits of realizing precise 3D features with sub-100 nm and rapid processes are attributed to the interference of coherent light diffracted by phase masks.In this review,to report the overall progress of PnP from 2003,we present a comprehensive understanding of PnP,including its brief history,the fundamental principles,symmetry control of 3D nanoarchitectures,material issues for the phase masks,and the process area expansion to the wafer-scale for the target applications.Finally,technical challenges and prospects are discussed for further development and practical applications of the PnP technique.
基金supported by the Welch Foundation grant E-1498NSF CAREER Award (CTS-0349228 to CC)+1 种基金grant DMR-0706627NIH R21 HD058985
文摘Functionalization of silicon substrate surfaces with a stable monolayer for resisting non-specific adsorption of proteins has attracted great interest,since it is directly relevant to the development of miniature,silicon-based biosensors and implantable microdevices,such as silicon-neuron interfaces.This brief review summarizes our contribution to the development of robust monolayers grown by surface hydrosilylation on atomically flat,hydrogen-terminated silicon surfaces.The review also outlines our strategy and progress on the fabrication of single molecule patterns on such monolayer platforms.
文摘We present measurements of the in situ, microscopic architecture of a self- assembled bilayer at the interface between a regularly nanopatterned surface and an aqueous sub-phase using neutron reflectometry. The substrate is patterned with a rectangular array of nanoscale holes. Because of the high quality of the pattern, using neutron reflectometry, we are able to map the surface-normal density distribution of the patterned silicon, the penetration of water into the pattern, and the distribution of a deposited film inside and outside of the etched holes. In this stud; 1,2-dilauroyl-sn-glycero-3-phosphocholine （DLPC） single bilayers were deposited on the hydrophilic patterned surface. For bilayers deposited either by vesicle fusion （VF） or by the Langmuir-Schaefer （L-S） technique, the most consistent model found to fit the data shows that the lipids form bilayer coatings on top of the substrate as well as the bottoms of the holes in an essentially conformal fashion. However, while there is a single bilayer on the unetched silicon surface, the lipids coating the bottoms of the holes form a complex bimodal structure consistent with a rough surface produced by the etching process. This study provides insight into film transfer both outside and inside regular nanopatterned features.
基金supported by the National Basic Research Program of China (2012CB932600)the National Natural Science Foundation of China(20725516, 90913014, 21028005 and 21103219)Shanghai Pujiang Program (11PJ1412000)
文摘Anisotropic nanopatterns have potentials in constructing novel plasmonic structures which have various applications in such as super-resolution microscopy, medicine, and sensors. However, it remains challenging to build big anisotropic nanopatterns that are suitable for big noble metal nanoparticles. Herein, we report a simple and reliable strategy for constructing DNA origami-based big anisotropic nanopatterns with controlled size and shape, nanoscale resolution, and fully addressability. Two kinds of basic DNA origami nanoblocks-cross-shaped and rectangular DNA origami units were used. We have demonstrated that by encoding nanoblocks' edges, anisotropic higher-order nanopatterns, such as dimer, trimer, tetramer and mini "windmill" like pentamer nanopatterns could be constructed. To show the potential use as template to direct the assembly of anisotropic nanoparticles arrays, a proof of concept work was conducted by anchoring streptavidin nanoparticles on the "windmill" template to form a chiral array. Significantly, these nanopatterns have the sizes of hundreds of nanometers, which are in principle also suitable for big noble metal nanoparticles arrays.
基金supported by the National Natural Science Foundation of China(Grant Nos.12075191,12388101,and 12241201)the Fundamental Research Funds for the Central Universities(Grant No.D5000230120)the Natural Science Basic Research Program of Shaanxi Province(Grant No.2023-JC-YB-541).
文摘The development of nanoelectronics and nanotechnologies has been boosted significantly by the emergence of 2D materials because of their atomic thickness and peculiar properties,and developing a universal,precise patterning technology for single-layer 2D materials is critical for assembling nanodevices.Demonstrated here is a nanomachining technique using electrical breakdown by an AFM tip to fabricate nanopores,nanostrips,and other nanostructures on demand.This can be achieved by voltage scanning or applying a constant voltage while moving the tip.By measuring the electrical current,the formation process on single-layer materials was shown quantitatively.The present results provide evidence of successful pattern fabrication on single-layer MoS2,boron nitride,and graphene,although further confirmation is still needed.The proposed method holds promise as a general nanomachining technology for the future.
基金the EPSRCDTA and the Institute of Materials and Processes,School of Engineering at the University of Edinburgh.
文摘The morphology of linear polybutadiene physisorbed on freshly cleaved mica from a dilute polymer solution is investigated through atomic force microscopy.A fine-structure study shows that the monolayer morphology in air(after rapid solvent evaporation)depends strongly on the molecular weight(Mw)of the linear polymer,the adsorbed amount,and the conformation adopted by the adsorbed polymer chains under good solvent conditions.The dependence of the observed polymer structure on Mw is most significant for samples with high surface density,where the intermolecular interactions among the adsorbed polymers are important.For high surface density,the adsorbed polymers tend to aggregate and minimize unfavorable contacts with air for all of the different Mw samples,leading to an isotropic structural pattern.These structural phenomena with increasing surface density are explained on the basis of the intermolecular interactions of the adsorbed polymers under good solvent conditions,and after the abrupt solvent evaporation corresponding to poor solvent conditions.The experimental observations are further discussed using the results obtained from molecular dynamics simulations of a simple coarse-grained model.
基金supported by the National Natural Science Foundation of China(Nos.51273048 and 51203025)Natural Science Foundation of Guangdong Province(No.S2012040007725)
文摘In this paper, microphase behavior of an ABC triblock copolymer, polystyrene-block-poly（2-vinylpyridine）-block- poly（ethylene oxide）, namely PS-b-P2VP-b-PEO, was systematically studied during spin-coating and solvent vapor annealing based on various parameters, including the types of the solvent, spin speed and thickness. The morphological features and the microdomain location of the different blocks were characterized by atomic force microscope （AFM） and high resolution transmission electron microscopy （HRTEM）. With increasing thickness, the order-order transition from nanopores array to the pattern of nanostripes was observed due to microdomain coarsening. These processes of pattern transformation were based on the selectivity of toluene for different blocks and on the contact time between solvent molecules and the three blocks. This work provides different templates for preparation of gold nanoparticle array on silicon wafer, which can be adopted as an active surface-enhanced Raman scattering （SERS） substrate for poly（3-hexylthiophene） （P3HT）.
文摘A method is presented for nano-patterning a diffraction grating on human hair with a focused ion beam. Strands of brown hair are patterned with hyperbolas and Archimedean spirals whose pitches range from 540 nm to 1040 nm. Exposure of the hair strands to white light at various incident angles demonstrates that light of varying wavelengths is diffracted by the diffraction gratings. The diffraction causes the brown strands of hair to reflect light from the entire range of visible light.
基金supported by the National Natural Science Foundation of China(Nos.52122507,52350411,and 12002289)the National Key R&D Program of China-Young Scientist Program(No.2023YFB3405500)+1 种基金The Independent Project of State Key Laboratory of Rail Transit Vehicle System(No.2023TPL-T04)Seong H.Kim was supported by the National Science Foundation of the USA(No.CMMI-1912199).
文摘The atomic edge structure of graphene governs its unique electronic properties with applications in nanoscale electronics and optoelectronics.To fully realize its potential,it is critical to develop a precision etching process producing graphene edges along desired directions.Here,we present a novel approach utilizing scanning probe lithography(SPL)facilitated by a mechanochemical atomic attrition process.This technique enables the fabrication of nanopatterns in single-layer graphene from graphene edges,precisely along the crystallographic orientation of zigzag(ZZ)and armchair(AC)edges,without inducing mechanical damage to the surrounding area.Density functional theory(DFT)calculations revealed that the dissociation of CC bonds by the SPL probe is mediated by the formation of interfacial bridge bonds between the graphene edge and the reactive silica surface.This SPL-based mechanochemical etching method enables the construction of various nanodevice structures with specific edge orientations,which allows the exploitation of their electronic properties.
