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
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.
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.
