A hierarchically‐structured nylon 6 (PA6) nanofiber membrane decorated with silver nanoparticles (Ag NPs) was fabricated by electrospinning and impregnation methods. The as‐fabricated hierarchically‐structured Ag/P...A hierarchically‐structured nylon 6 (PA6) nanofiber membrane decorated with silver nanoparticles (Ag NPs) was fabricated by electrospinning and impregnation methods. The as‐fabricated hierarchically‐structured Ag/PA6 nanofiber membrane (HS‐Ag/PA6 NM) exhibits a morphology in which Ag NPs are deposited on the surfaces of both thick fibers and thin fibers. The content and size of theAg NPs can be controlled by varying the concentration of the silver colloid solution. Compared with the non‐hierarchically‐structured Ag/PA6 nanofiber membrane, HS‐Ag/PA6 NM has a higher specificsurface area and exhibits a higher degradation rate for methylene blue of 81.8%–98.1% within2 h. HS‐Ag/PA6 NM can be easily recycled and exhibits good reusability. It retains a degradation rate for methylene blue of 83.5% after five consecutive cycles. The hierarchically‐structured nanofiber membrane is therefore a potential nanocatalyst.展开更多
The microstructures of pearlitic steel wire rods and steel wires are commonly characterized by secondary electron imaging (SEI)technique using scanning electron microscopy(SEM).In this work,a back-scattered electron i...The microstructures of pearlitic steel wire rods and steel wires are commonly characterized by secondary electron imaging (SEI)technique using scanning electron microscopy(SEM).In this work,a back-scattered electron imaging(BSEI)method is proposed to determine the microstructures of undeformed and deformed pearlitic steels with nanometer scale pearlite lamellae.The results indicate that BSEI technique can characterize the pearlite lamellas veritably and is effective in quantitative measurement of the mean size of pearlite interlamellar spacing.To some extent,BSEI method is more suitable than SEI technique for studying undeformed and not severely deformed pearlitic steels.展开更多
As the typical systems of nano structures, nanotubes can be widely applied in mechanical electronics, mechanical manufacture and other fields at nano scales. The superior dynamical properties of nanotubes have become ...As the typical systems of nano structures, nanotubes can be widely applied in mechanical electronics, mechanical manufacture and other fields at nano scales. The superior dynamical properties of nanotubes have become a hot topic. Furthermore, there are always complicated conditions for practical engineering (e.g. initial stress/strain, temperature change for external environment and the interaction between the structure and elastic matrix). Then, it is important to establish the proper model and apply the effective analysis method. By using the nonlocal continuum method, this paper reviews the recent progress of dynamical properties of micro structures at nano scales. The discussion is focused on dynamical behaviors of nanotubes, including vibration, wave propagation and fluid-structure interaction, etc. At last, conclusions and prospects in future studies are discussed.展开更多
The microstructure, wettability and chemical composition of the butterfly wing surfaces were investigated by a scanning electron microscope, a contact angle meter and a Fourier transform infrared spectrometer. The mic...The microstructure, wettability and chemical composition of the butterfly wing surfaces were investigated by a scanning electron microscope, a contact angle meter and a Fourier transform infrared spectrometer. The micro/nano structural models for hydrophobicity of the butterfly wing surfaces were established on the basis of the Cassie equation. The hydrophobicity mechanisms were discussed from the perspective of biological coupling. The butterfly wing surfaces are composed of naturally hydrophobic material and possess micro/nano hierarchical structures, including primary structure （micrometric scales）, secondary structure （nano longitudinal ridges and lateral bridges） and tertiary structure （nano stripes）. The wing surfaces exhibit high hydrophobicity （contact angle 138°-157°） and low adhesion （sliding angle 1°-3°）. The micromorphology and self-cleaning performance of the wing surfaces demonstrate remarkable anisotropism. The special complex wettability ascribes to a coupling effect of the material element and the structure element. In microdimension, the smaller the width and the bigger the spacing of the scale, the stronger the hydrophobicity of the wing surfaces. In nano-dimension, the smaller the height and the smaller the width and the bigger the spacing of the longitudinal ridge, the stronger the hydrophobicity of the wing surfaces. This work promotes our understanding of the hydrophobicity mechanism of bio-surfaces and may bring inspiration for biomimetic design and preparation of smart interfacial materials.展开更多
Various nanostructures of the organic semiconductor (OSC)films have been reported to enhance the organic field-effect transistors (OFETs)sensing performance. However,complicated fabrication processes hinder their ap- ...Various nanostructures of the organic semiconductor (OSC)films have been reported to enhance the organic field-effect transistors (OFETs)sensing performance. However,complicated fabrication processes hinder their ap- plications.In this work,we have effectively enhanced the sensitivity of the OFET-based sensors only by adjusting substrate temperature in OSC preparation and surface treatment of the dielectric layer.The relative sensitivity of the device can be enhanced by 5 times.The flexible sensors with polymer dielectric also exhibit high sensitivity because the less smooth surface of the polymer provides the OSCs with smaller grain size.Therefore,this work reveals the trade-off effects of the OSCs grain size on both transistor characteristic and chemic.al sensing performance,and provides a simple and extensively applicable strategy for OFETs sensitivity improvement.展开更多
A simple method to fabricate one-dimensional(1-D) and two-dimensional(2-D) ordered micro- and nano-scale patterns is developed based on the original masters from optical discs, using nanoimprint technology and soft st...A simple method to fabricate one-dimensional(1-D) and two-dimensional(2-D) ordered micro- and nano-scale patterns is developed based on the original masters from optical discs, using nanoimprint technology and soft stamps. Polydimethylsiloxane(PDMS) was used to replicate the negative image of the 1-D grating pattern on the masters of CD-R, DVD-R and BD-R optical discs, respectively, and then the 1-D pattern on one of the PDMS stamps was transferred to a blank polycarbonate(PC) substrate by nanoimprint. The 2-D ordered patterns were fabricated by the second imprinting using another PDMS stamp. Different 2-D periodic patterns were obtained depending on the PDMS stamps and the angle between the two times of imprints. This method may provide a way for the fabrication of complex 2-D patterns using simple 1-D masters.展开更多
The present paper develops the scaling theory of polyelectrolyte nanogels in dilute and semidilute solutions. The dependencies of the nanogel dimension on branching topology, charge fraction, subchain length, segment ...The present paper develops the scaling theory of polyelectrolyte nanogels in dilute and semidilute solutions. The dependencies of the nanogel dimension on branching topology, charge fraction, subchain length, segment number, solution concentration are obtained. For a single polyeleetrolyte nanogel in salt free solution, the nanogel may be swelled by the Coulombie repulsion （the so-called polyelectrolyte regime） or the osmotic eounterion pressure （the so-called osmotic regime）. Characteristics and boundaries between different regimes of a single polyelectrolyte nanogel are summarized. In dilute solution, the nanogels in polyeleetrolyte regime will distribute orderly with the increase of concentration. While the nanogels in osmotic regime will always distribute randomly. Different concentration dependencies of the size of a nanogel in polyeleetrolyte regime and in osmotic regime are also explored.展开更多
基金supported by the National Natural Science Foundation of China (51673148)National Basic Research Program of China (2014CB660813)+2 种基金National Key Technology Support Program (2015BAE01B03)Innovation Fund for Technology of China (14C26211200298)Innovation Fund for Technology of Tianjin (14TXGCCX00014,14ZXCXGX00776)~~
文摘A hierarchically‐structured nylon 6 (PA6) nanofiber membrane decorated with silver nanoparticles (Ag NPs) was fabricated by electrospinning and impregnation methods. The as‐fabricated hierarchically‐structured Ag/PA6 nanofiber membrane (HS‐Ag/PA6 NM) exhibits a morphology in which Ag NPs are deposited on the surfaces of both thick fibers and thin fibers. The content and size of theAg NPs can be controlled by varying the concentration of the silver colloid solution. Compared with the non‐hierarchically‐structured Ag/PA6 nanofiber membrane, HS‐Ag/PA6 NM has a higher specificsurface area and exhibits a higher degradation rate for methylene blue of 81.8%–98.1% within2 h. HS‐Ag/PA6 NM can be easily recycled and exhibits good reusability. It retains a degradation rate for methylene blue of 83.5% after five consecutive cycles. The hierarchically‐structured nanofiber membrane is therefore a potential nanocatalyst.
基金supported by the National Key Technology R&D Program of China(Grant No.2007BAE15B01)the Major Program of the National Natural Science Foundation of China(Grant No.50890170)
文摘The microstructures of pearlitic steel wire rods and steel wires are commonly characterized by secondary electron imaging (SEI)technique using scanning electron microscopy(SEM).In this work,a back-scattered electron imaging(BSEI)method is proposed to determine the microstructures of undeformed and deformed pearlitic steels with nanometer scale pearlite lamellae.The results indicate that BSEI technique can characterize the pearlite lamellas veritably and is effective in quantitative measurement of the mean size of pearlite interlamellar spacing.To some extent,BSEI method is more suitable than SEI technique for studying undeformed and not severely deformed pearlitic steels.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11002045, 11172084, 10632020 and 10672017)
文摘As the typical systems of nano structures, nanotubes can be widely applied in mechanical electronics, mechanical manufacture and other fields at nano scales. The superior dynamical properties of nanotubes have become a hot topic. Furthermore, there are always complicated conditions for practical engineering (e.g. initial stress/strain, temperature change for external environment and the interaction between the structure and elastic matrix). Then, it is important to establish the proper model and apply the effective analysis method. By using the nonlocal continuum method, this paper reviews the recent progress of dynamical properties of micro structures at nano scales. The discussion is focused on dynamical behaviors of nanotubes, including vibration, wave propagation and fluid-structure interaction, etc. At last, conclusions and prospects in future studies are discussed.
基金supported by the National Natural Science Foundation of China(50875108)the Natural Science Foundation of Jilin Province,China(201115162)the Open Fundof Key Laboratory of Bionic Engineering of Ministry of Education,Jilin University(K201004)
文摘The microstructure, wettability and chemical composition of the butterfly wing surfaces were investigated by a scanning electron microscope, a contact angle meter and a Fourier transform infrared spectrometer. The micro/nano structural models for hydrophobicity of the butterfly wing surfaces were established on the basis of the Cassie equation. The hydrophobicity mechanisms were discussed from the perspective of biological coupling. The butterfly wing surfaces are composed of naturally hydrophobic material and possess micro/nano hierarchical structures, including primary structure （micrometric scales）, secondary structure （nano longitudinal ridges and lateral bridges） and tertiary structure （nano stripes）. The wing surfaces exhibit high hydrophobicity （contact angle 138°-157°） and low adhesion （sliding angle 1°-3°）. The micromorphology and self-cleaning performance of the wing surfaces demonstrate remarkable anisotropism. The special complex wettability ascribes to a coupling effect of the material element and the structure element. In microdimension, the smaller the width and the bigger the spacing of the scale, the stronger the hydrophobicity of the wing surfaces. In nano-dimension, the smaller the height and the smaller the width and the bigger the spacing of the longitudinal ridge, the stronger the hydrophobicity of the wing surfaces. This work promotes our understanding of the hydrophobicity mechanism of bio-surfaces and may bring inspiration for biomimetic design and preparation of smart interfacial materials.
基金supported by the National Natural Science Foundation of China (51603151 and 51741302)the National Key Research and Development Program of China (2017YFA0103900 & 2017YFA0103904)+1 种基金 Science & Technology Foundation of Shanghai (17JC1404600) the Fundamental Research Funds for the Central Universities.
文摘Various nanostructures of the organic semiconductor (OSC)films have been reported to enhance the organic field-effect transistors (OFETs)sensing performance. However,complicated fabrication processes hinder their ap- plications.In this work,we have effectively enhanced the sensitivity of the OFET-based sensors only by adjusting substrate temperature in OSC preparation and surface treatment of the dielectric layer.The relative sensitivity of the device can be enhanced by 5 times.The flexible sensors with polymer dielectric also exhibit high sensitivity because the less smooth surface of the polymer provides the OSCs with smaller grain size.Therefore,this work reveals the trade-off effects of the OSCs grain size on both transistor characteristic and chemic.al sensing performance,and provides a simple and extensively applicable strategy for OFETs sensitivity improvement.
基金supported by the National Natural Science Foundation of China(Nos.11504259,21575098 and 21505098)the Shanxi International Cooperation Project(No.2015081019)+2 种基金the Shanxi Scholarship Council(No.2013-038)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2015123)the Scientific Research Starting Foundation from Taiyuan University of Technology(No.tyut-rc201162a)
文摘A simple method to fabricate one-dimensional(1-D) and two-dimensional(2-D) ordered micro- and nano-scale patterns is developed based on the original masters from optical discs, using nanoimprint technology and soft stamps. Polydimethylsiloxane(PDMS) was used to replicate the negative image of the 1-D grating pattern on the masters of CD-R, DVD-R and BD-R optical discs, respectively, and then the 1-D pattern on one of the PDMS stamps was transferred to a blank polycarbonate(PC) substrate by nanoimprint. The 2-D ordered patterns were fabricated by the second imprinting using another PDMS stamp. Different 2-D periodic patterns were obtained depending on the PDMS stamps and the angle between the two times of imprints. This method may provide a way for the fabrication of complex 2-D patterns using simple 1-D masters.
基金Supported by China Earthquake Administration under Grant No.20150112National Natural Science Foundation of China under Grant No.21504014
文摘The present paper develops the scaling theory of polyelectrolyte nanogels in dilute and semidilute solutions. The dependencies of the nanogel dimension on branching topology, charge fraction, subchain length, segment number, solution concentration are obtained. For a single polyeleetrolyte nanogel in salt free solution, the nanogel may be swelled by the Coulombie repulsion （the so-called polyelectrolyte regime） or the osmotic eounterion pressure （the so-called osmotic regime）. Characteristics and boundaries between different regimes of a single polyelectrolyte nanogel are summarized. In dilute solution, the nanogels in polyeleetrolyte regime will distribute orderly with the increase of concentration. While the nanogels in osmotic regime will always distribute randomly. Different concentration dependencies of the size of a nanogel in polyeleetrolyte regime and in osmotic regime are also explored.
