The microstructural evolution at the liquid Al/solid Ni interface during remelting and resolidification was dynamically observed by using synchrotron radiography.The formation and growth behavior of Al_(3)Ni_(2) and A...The microstructural evolution at the liquid Al/solid Ni interface during remelting and resolidification was dynamically observed by using synchrotron radiography.The formation and growth behavior of Al_(3)Ni_(2) and Al_(3)Ni brittle intermetallic compounds(IMCs)under different conditions was investigated,and the formation mechanisms of dendritic Al_(3)Ni crystals with different morphologies were elucidated.The increasing remelting cycles accelerated the formation of Al_(3)Ni_(2) layer and the growth of Al_(3)Ni IMCs.The increased-step heating temperatures and time promoted the morphological transition from faceted to non-faceted dendritic Al_(3)Ni,which was attributed to the enhanced undercooling during solidification and incompletely remelted Al_(3)Ni IMCs during remelting.The growth of regular Al_(3)Ni dendrites was dominated by coalescence of secondary dendrite arms,while the growth of irregular dendrites Al_(3)Ni was controlled by dendrite merging,radial melting and axial melting of secondary arms.The axially free dendritic Al_(3)Ni was attributed to the small distance between adjacent main trunks,and the dense secondary arms promoted the formation of local solute depletion regions.展开更多
The hydration state of amphiphilic block copolymers during the self-assembly transition is closely related to the structure and properties of copolymers. In this study, the temperature-induced self-assembly of copolym...The hydration state of amphiphilic block copolymers during the self-assembly transition is closely related to the structure and properties of copolymers. In this study, the temperature-induced self-assembly of copolymer poly(N,N-dimethylacrylamide)-poly(diacetone acrylamide)(PDMAA_(30)-PDAAM_(60))_(2)in aqueous solution was monitored by near-infrared spectroscopy with water as a probe. The wavelet packet transform was employed to improve the spectral resolution. The spectral information of hydrated water surrounding the hydrophilic PDMAA and hydrophobic PDAAM blocks was then extracted, revealing the significant roles of water in morphological transition of the copolymer from spherical to worm-like micelles. Specifically, water molecules interacting with N atoms and C=O groups of the hydrophilic block gradually decrease during the morphological transition, while hydrogen-bond structures NH–CO of the hydrophobic block gradually break, bringing more water molecules into contact with the hydrophobic block. This work provides a foundation for exploring the role of water molecules during the self-assembly transition of complex block copolymers.展开更多
The initial stages of multilayer Co thin film grown on Cu(111) surface were simulated by means of kinetic Monte Carlo (KMC) method, where the realistic growth model and physical parameters were presented. The effects ...The initial stages of multilayer Co thin film grown on Cu(111) surface were simulated by means of kinetic Monte Carlo (KMC) method, where the realistic growth model and physical parameters were presented. The effects of edge diffusion along the islands and mass transport between interlayers were included in the simulation model. Emphasis was placed on revealing the transition of growth morphology in heteroepitaxial Co/Cu(111) system with the changing of surface temperature. The simulation results show that the dendritic islands form at low temperature (T=210 K), while compact islands grow at room temperature (RT). The Volmer-Webber (three-dimensional, 3D) growth mode is presented due to the relative higher Ehrlich-Schwoebel (ES) barrier. Our simulation results are in good agreement with the real scanning tunneling microscopy (STM) experiments.展开更多
A short-chain triblock copolymer EO9-DMS7-EO9 was synthesized by coupling reaction of allyl-terminated poly（ethylene oxide） and Si-H-terminated poly（dimethylsiloxane）. The structure and purity of synthesized copol...A short-chain triblock copolymer EO9-DMS7-EO9 was synthesized by coupling reaction of allyl-terminated poly（ethylene oxide） and Si-H-terminated poly（dimethylsiloxane）. The structure and purity of synthesized copolymer was carefully characterized. Self-assembly behavior of EO9-DMST-EO9 triblock copolymer in water was investigated. And it was found that along with the increase of copolymer concentration, morphology of self-assembled aggregates transits from sphere to rod. A plausible understanding of the morphology transition for the investigated triblock copolymer was proposed.展开更多
This paper briefly reviews the recent research on the near rapid directional solidification and microstructure superfining. The morphology transitions and the corresponding mechanical properties are presented. The cri...This paper briefly reviews the recent research on the near rapid directional solidification and microstructure superfining. The morphology transitions and the corresponding mechanical properties are presented. The critical velocities relevant to the morphology transitions are comprehensively given. Meanwhile the solidification characteristics near absolute stability limit are studied.It can be clearly seen that the superfine microstructures possess extremely better properties compared with the conventional microstructures.展开更多
The formation of nanoscale water capillary bridges(WCBs) between chemically heterogeneous(patchy) surfaces plays an important role in different scientific and engineering applications, including nanolithography, collo...The formation of nanoscale water capillary bridges(WCBs) between chemically heterogeneous(patchy) surfaces plays an important role in different scientific and engineering applications, including nanolithography, colloidal aggregation, and bioinspired adhesion. However, the properties of WCB of nanoscale dimensions remain unclear. Using molecular dynamics simulations, we investigate the geometrical and thermodynamic properties of WCB confined between chemically heterogeneous surfaces composed of circular hydrophilic patches on a hydrophobic background. We find that macroscopic capillary theory provides a good description of the WCB geometry and forces induced by the WCB on the confining surfaces even in the case of surface patches with diameters of only 4 nm. Upon stretching, the WCB contact angle changes from hydrophobic-like values(θ > 90°) to hydrophilic-like values(θ < 90°) until it finally breaks down into two droplets at wall separations of ~9–10 nm. We also show that the studied nanoscale WCB can be used to store relevant amounts of energy EPand explore how the walls patch geometry can be improved in order to maximize EP. Our findings show that nanoscale WCB can, in principle, be exploited for the design of clean energy storage devices as well as actuators that respond to changes in relative humidity. The present results can also be of crucial importance for the understanding of water transport in nanoporous media and nanoscale engineering systems.展开更多
Although gas-filled microbubbles with high echogenicity are widely applied in clinical ultrasonography, the micron scale particle size impedes their use in the treatment of solid tumors, which are accessible to object...Although gas-filled microbubbles with high echogenicity are widely applied in clinical ultrasonography, the micron scale particle size impedes their use in the treatment of solid tumors, which are accessible to objects less than several hundred nanometers. We herein propose an unusual approach involving a pH-induced core-shell micelle-to-vesicle transition to prepare ultrasound-sensitive polymeric nanospheres （polymersomes in structure） possessing multiple features, including nanosize, monodispersity, and incorporation of a phase- transitional imaging agent into the aqueous lumen. These features are not achievable via the conventional double-emulsion method for polymersome preparation. The nanospheres were constructed based on a novel triblock copolymer with dual pH sensitivity. The liquid-to-gas phase transition of the imaging agent induced by external low-frequency ultrasound may destroy the nanospheres for a rapid drug release, with simultaneous tissue-penetrating drug delivery inside a tumor. These effects may provide new opportunities for the development of an effective cancer therapy with few adverse effects.展开更多
Dynamic transitions of supramolecular assemblies between lower-order structures and higher-order superhelical structures(e.g.,double-helical DNA,helical biopolymers)are of vital importance in many physiological proces...Dynamic transitions of supramolecular assemblies between lower-order structures and higher-order superhelical structures(e.g.,double-helical DNA,helical biopolymers)are of vital importance in many physiological processes,but still remain a great challenge to be realized in artificially assembled systems.Herein,a novel biphenyl central core symmetrically coupled with phenylalanine groups drives the construction of the dynamic superhelix.展开更多
A Fe-12Cr-2W-0.2Zr-0.1Ti-0.35Y_(2)O_(3)ODS ferritic alloy was prepared by ball milling,hot isostatic pressing(HIP)and thermomechanical processing herein.The evolution of oxide nanoparticles(ONPs)with differ-ent interm...A Fe-12Cr-2W-0.2Zr-0.1Ti-0.35Y_(2)O_(3)ODS ferritic alloy was prepared by ball milling,hot isostatic pressing(HIP)and thermomechanical processing herein.The evolution of oxide nanoparticles(ONPs)with differ-ent intermediate annealing temperatures of thermomechanical processing and its effect on microstructure and mechanical properties of the ODS alloy were investigated.The result shows that the intermediate annealing temperatures played a decisive role in the size,morphology and structure of nanoparticles in the final alloy since this was attributed to the fact that fine particles were dissolved through dislocation shearing during cold deformation and then re-precipitated during subsequent heat treatment.The high intermediate annealing temperature promotes the growth of the near-spherical ONPs,while the ellip-soidal nanoparticles are developed at relatively low temperature.Meanwhile,the structural change of the ONPs was also facilitated by the dissolution-reprecipitation behavior.The predominant Y_(2)(Zr_(y)Ti_(1−y))_(2)O_(7)with cubic pyrochlore phase in as-HIPed alloy can be transformed into Y_(4)Zr_(3)O_(12)particles with rhom-bohedral structure during the thermomechanical treatment.However,compared with the change in size of ONPs,the change in morphology and structure of ONPs has no obvious influence on the mechanical strength.Different intermediate annealing temperatures play a different role in the coarsening of ONPs during thermomechanical treatment,which makes the alloy annealed at low temperature exhibiting more uniform distribution of ONPs and better mechanical properties.展开更多
The research on the supramolecular hyperbranched polymers(SHPs) that combines the advantages of supramolecular polymer and hyperbranched architecture has attracted considerable interests in many applications. Here we ...The research on the supramolecular hyperbranched polymers(SHPs) that combines the advantages of supramolecular polymer and hyperbranched architecture has attracted considerable interests in many applications. Here we demonstrate a simple approach to prepare POSS-embedded supramolecular hyperbranched polymers(POSS-SHPs) with varied morphology and size by controlling monomer concentration and mixed solvents. The SHPs formations can further transfer into the core-shell structured micelles by addition of competitive vips based on the double supramolecular driving forces.展开更多
Dear Editor,Pathogenic fungi often undergo rapid morphological transitions to adapt to dynamic environments during infections and in natural habitats(Biswas et al.,2007;Prasad and Tippana,2023).These phenotypic transi...Dear Editor,Pathogenic fungi often undergo rapid morphological transitions to adapt to dynamic environments during infections and in natural habitats(Biswas et al.,2007;Prasad and Tippana,2023).These phenotypic transitions are primarily driven by environmental cues through nongenetic alterations,including epigenetic,transcriptional,and post-transcriptional modifications(Biswas et al.,2007).展开更多
A definitive understanding of the interplay between protein binding/migration and membrane curvature evolution is emerging but needs further study.The mechanisms defining such phenomena are critical to intracellular t...A definitive understanding of the interplay between protein binding/migration and membrane curvature evolution is emerging but needs further study.The mechanisms defining such phenomena are critical to intracellular transport and trafficking of proteins.Among trafficking modalities,exosomes have drawn attention in cancer research as these nano-sized naturally occurring vehicles are implicated in intercellular communication in the tumor microenvironment,suppressing anti-tumor immunity and preparing the metastatic niche for progression.A significant question in the field is how the release and composition of tumor exosomes are regulated.In this perspective article,we explore how physical factors such as geometry and tissue mechanics regulate cell cortical tension to influence exosome production by co-opting the biophysics as well as the signaling dynamics of intracellular trafficking pathways and how these exosomes contribute to the suppression of anti-tumor immunity and promote metastasis.We describe a multiscale modeling approach whose impact goes beyond the fundamental investigation of specific cellular processes toward actual clinical translation.Exosomal mechanisms are critical to developing and approving liquid biopsy technologies,poised to transform future non-invasive,longitudinal profiling of evolving tumors and resistance to cancer therapies to bring us one step closer to the promise of personalized medicine.展开更多
Latest advances have witnessed the laser induction process on polyimide(PI)films for the formation of porous graphene.Herein,a fully converted graphene film was prepared by Nd:YAG laser scribing a gelatin coated PI fi...Latest advances have witnessed the laser induction process on polyimide(PI)films for the formation of porous graphene.Herein,a fully converted graphene film was prepared by Nd:YAG laser scribing a gelatin coated PI film.It was found that the gelatin played the role of"shield"well in absorbing intense laser impact and benefit for the surface morphology modulation.Laser treatment lower than a critical fluence point of~4.00 J mm^(-2) contributed to a crater-like surface morphology due to the dispersed nature of Nd:YAG laser beam.By tuning laser fluence above the threshold,carbonized surface turned into continuous morphology.A fluid dynamics process accompanied by outgassing occurred during the carbonization,and the surface morphology gradually varied from stretched droplets to porous strips and finally to amorphous porous structures.The morphology evolution in combination with surface chemistry is responsible for the significant wettability transition from superhydrophobic to superhydrophilic,and a Janus superhydrophobic/superhydrophilic surface wettability was achieved under a laser fluence of~8.00 J mm^(-2).Eventually,microsupercapacitors(MSCs)were fabricated to show the great potential of our prepared graphene in flexible electronics.展开更多
基金financially supported by the National Natural Science Foundation of China-Outstanding Young Scholars(52325407)National Natural Science Foundation of China(52474401)+1 种基金Project funded by China Postdoctoral Science Foundation(No.2022M712919)Guangdong Basic and Applied Basic Research Foundation(2023A1515140124,2025A1515012873,2022A1515140028,2022A1515010761).
文摘The microstructural evolution at the liquid Al/solid Ni interface during remelting and resolidification was dynamically observed by using synchrotron radiography.The formation and growth behavior of Al_(3)Ni_(2) and Al_(3)Ni brittle intermetallic compounds(IMCs)under different conditions was investigated,and the formation mechanisms of dendritic Al_(3)Ni crystals with different morphologies were elucidated.The increasing remelting cycles accelerated the formation of Al_(3)Ni_(2) layer and the growth of Al_(3)Ni IMCs.The increased-step heating temperatures and time promoted the morphological transition from faceted to non-faceted dendritic Al_(3)Ni,which was attributed to the enhanced undercooling during solidification and incompletely remelted Al_(3)Ni IMCs during remelting.The growth of regular Al_(3)Ni dendrites was dominated by coalescence of secondary dendrite arms,while the growth of irregular dendrites Al_(3)Ni was controlled by dendrite merging,radial melting and axial melting of secondary arms.The axially free dendritic Al_(3)Ni was attributed to the small distance between adjacent main trunks,and the dense secondary arms promoted the formation of local solute depletion regions.
基金supported by the National Natural Science Foundation of China (Nos. 22174075 and 22374082)the Haihe Laboratory of Sustainable Chemical Transformations。
文摘The hydration state of amphiphilic block copolymers during the self-assembly transition is closely related to the structure and properties of copolymers. In this study, the temperature-induced self-assembly of copolymer poly(N,N-dimethylacrylamide)-poly(diacetone acrylamide)(PDMAA_(30)-PDAAM_(60))_(2)in aqueous solution was monitored by near-infrared spectroscopy with water as a probe. The wavelet packet transform was employed to improve the spectral resolution. The spectral information of hydrated water surrounding the hydrophilic PDMAA and hydrophobic PDAAM blocks was then extracted, revealing the significant roles of water in morphological transition of the copolymer from spherical to worm-like micelles. Specifically, water molecules interacting with N atoms and C=O groups of the hydrophilic block gradually decrease during the morphological transition, while hydrogen-bond structures NH–CO of the hydrophobic block gradually break, bringing more water molecules into contact with the hydrophobic block. This work provides a foundation for exploring the role of water molecules during the self-assembly transition of complex block copolymers.
基金This was work was supported by the Natural Science Foundation for Young Scientists of Zhejiang Province (No.RC02069).
文摘The initial stages of multilayer Co thin film grown on Cu(111) surface were simulated by means of kinetic Monte Carlo (KMC) method, where the realistic growth model and physical parameters were presented. The effects of edge diffusion along the islands and mass transport between interlayers were included in the simulation model. Emphasis was placed on revealing the transition of growth morphology in heteroepitaxial Co/Cu(111) system with the changing of surface temperature. The simulation results show that the dendritic islands form at low temperature (T=210 K), while compact islands grow at room temperature (RT). The Volmer-Webber (three-dimensional, 3D) growth mode is presented due to the relative higher Ehrlich-Schwoebel (ES) barrier. Our simulation results are in good agreement with the real scanning tunneling microscopy (STM) experiments.
基金supported by National Natural Science Foundation of China (No.20606029)China Postdoctoral Science Foundation (No.20070420230).
文摘A short-chain triblock copolymer EO9-DMS7-EO9 was synthesized by coupling reaction of allyl-terminated poly（ethylene oxide） and Si-H-terminated poly（dimethylsiloxane）. The structure and purity of synthesized copolymer was carefully characterized. Self-assembly behavior of EO9-DMST-EO9 triblock copolymer in water was investigated. And it was found that along with the increase of copolymer concentration, morphology of self-assembled aggregates transits from sphere to rod. A plausible understanding of the morphology transition for the investigated triblock copolymer was proposed.
文摘This paper briefly reviews the recent research on the near rapid directional solidification and microstructure superfining. The morphology transitions and the corresponding mechanical properties are presented. The critical velocities relevant to the morphology transitions are comprehensively given. Meanwhile the solidification characteristics near absolute stability limit are studied.It can be clearly seen that the superfine microstructures possess extremely better properties compared with the conventional microstructures.
基金Project support by the National Natural Science Foundation of China(Grant Nos.11525520 and 11935002)the National Key Research and Development Program of China(Grant No.2016YFA0300901).
文摘The formation of nanoscale water capillary bridges(WCBs) between chemically heterogeneous(patchy) surfaces plays an important role in different scientific and engineering applications, including nanolithography, colloidal aggregation, and bioinspired adhesion. However, the properties of WCB of nanoscale dimensions remain unclear. Using molecular dynamics simulations, we investigate the geometrical and thermodynamic properties of WCB confined between chemically heterogeneous surfaces composed of circular hydrophilic patches on a hydrophobic background. We find that macroscopic capillary theory provides a good description of the WCB geometry and forces induced by the WCB on the confining surfaces even in the case of surface patches with diameters of only 4 nm. Upon stretching, the WCB contact angle changes from hydrophobic-like values(θ > 90°) to hydrophilic-like values(θ < 90°) until it finally breaks down into two droplets at wall separations of ~9–10 nm. We also show that the studied nanoscale WCB can be used to store relevant amounts of energy EPand explore how the walls patch geometry can be improved in order to maximize EP. Our findings show that nanoscale WCB can, in principle, be exploited for the design of clean energy storage devices as well as actuators that respond to changes in relative humidity. The present results can also be of crucial importance for the understanding of water transport in nanoporous media and nanoscale engineering systems.
基金This work was supported by the National Basic Research Program of China （No. 2015CB755500）, the National Natural Science Foundation of China （Nos. U1401242, 51225305, and 81430038）, the Natural Science Foundation of the Guangdong Province （No. 2014A030312018）, the Guangdong Innovative and Entrepreneurial Research Team Program （No. 2013S086）, and the Macao Science and Technology Development Fund （No. 096/2015/A3）.
文摘Although gas-filled microbubbles with high echogenicity are widely applied in clinical ultrasonography, the micron scale particle size impedes their use in the treatment of solid tumors, which are accessible to objects less than several hundred nanometers. We herein propose an unusual approach involving a pH-induced core-shell micelle-to-vesicle transition to prepare ultrasound-sensitive polymeric nanospheres （polymersomes in structure） possessing multiple features, including nanosize, monodispersity, and incorporation of a phase- transitional imaging agent into the aqueous lumen. These features are not achievable via the conventional double-emulsion method for polymersome preparation. The nanospheres were constructed based on a novel triblock copolymer with dual pH sensitivity. The liquid-to-gas phase transition of the imaging agent induced by external low-frequency ultrasound may destroy the nanospheres for a rapid drug release, with simultaneous tissue-penetrating drug delivery inside a tumor. These effects may provide new opportunities for the development of an effective cancer therapy with few adverse effects.
基金support of this research from the National Natural Science Foundation of China(NSFC nos.51833006 and 52003154)the Innovation Program of the Shanghai Municipal Education Commission(no.201701070002E00061)+2 种基金the Shanghai Pujiang Program(no.20PJ1407400),the Natural Science Foundation of Shanghai(no.20ZR1425500)SJTU Transmed Awards Research(no.WF5401X62X603)the Science and Technology Commission of Shanghai Municipality(no.20S31904600).
文摘Dynamic transitions of supramolecular assemblies between lower-order structures and higher-order superhelical structures(e.g.,double-helical DNA,helical biopolymers)are of vital importance in many physiological processes,but still remain a great challenge to be realized in artificially assembled systems.Herein,a novel biphenyl central core symmetrically coupled with phenylalanine groups drives the construction of the dynamic superhelix.
基金financially supported by the Research Fund of Nuclear Materials of China Atomic Energy Authority(No.ICNM-2023-YZ-03).
文摘A Fe-12Cr-2W-0.2Zr-0.1Ti-0.35Y_(2)O_(3)ODS ferritic alloy was prepared by ball milling,hot isostatic pressing(HIP)and thermomechanical processing herein.The evolution of oxide nanoparticles(ONPs)with differ-ent intermediate annealing temperatures of thermomechanical processing and its effect on microstructure and mechanical properties of the ODS alloy were investigated.The result shows that the intermediate annealing temperatures played a decisive role in the size,morphology and structure of nanoparticles in the final alloy since this was attributed to the fact that fine particles were dissolved through dislocation shearing during cold deformation and then re-precipitated during subsequent heat treatment.The high intermediate annealing temperature promotes the growth of the near-spherical ONPs,while the ellip-soidal nanoparticles are developed at relatively low temperature.Meanwhile,the structural change of the ONPs was also facilitated by the dissolution-reprecipitation behavior.The predominant Y_(2)(Zr_(y)Ti_(1−y))_(2)O_(7)with cubic pyrochlore phase in as-HIPed alloy can be transformed into Y_(4)Zr_(3)O_(12)particles with rhom-bohedral structure during the thermomechanical treatment.However,compared with the change in size of ONPs,the change in morphology and structure of ONPs has no obvious influence on the mechanical strength.Different intermediate annealing temperatures play a different role in the coarsening of ONPs during thermomechanical treatment,which makes the alloy annealed at low temperature exhibiting more uniform distribution of ONPs and better mechanical properties.
基金supported by the National Natural Science Foundation of China(21504096,21674120,21474115)Ministry of Science and Technology of China(2014CB932200)“Young Thousand Talents”Program
文摘The research on the supramolecular hyperbranched polymers(SHPs) that combines the advantages of supramolecular polymer and hyperbranched architecture has attracted considerable interests in many applications. Here we demonstrate a simple approach to prepare POSS-embedded supramolecular hyperbranched polymers(POSS-SHPs) with varied morphology and size by controlling monomer concentration and mixed solvents. The SHPs formations can further transfer into the core-shell structured micelles by addition of competitive vips based on the double supramolecular driving forces.
基金supported by the National Key Research and Development Program of China(2022YFC2303000,2021YFC2300400)the National Natural Science Foundation of China(31930005,82272359,32170194,32170193,82202546)the China Postdoctoral Science Foundation(2023M730684,2022M720804)。
文摘Dear Editor,Pathogenic fungi often undergo rapid morphological transitions to adapt to dynamic environments during infections and in natural habitats(Biswas et al.,2007;Prasad and Tippana,2023).These phenotypic transitions are primarily driven by environmental cues through nongenetic alterations,including epigenetic,transcriptional,and post-transcriptional modifications(Biswas et al.,2007).
基金received funding from the National Institutes of Health under R35GM136259 and U01CA250044supported by the National Cancer Institute and Leidos Biomedical Research,Inc.under contract 15X008 with Frederick National Laboratory for Cancer Research.Computational resources were partly available from the extreme science and engineering discovery environment(XSEDE)under grant MCB200101.
文摘A definitive understanding of the interplay between protein binding/migration and membrane curvature evolution is emerging but needs further study.The mechanisms defining such phenomena are critical to intracellular transport and trafficking of proteins.Among trafficking modalities,exosomes have drawn attention in cancer research as these nano-sized naturally occurring vehicles are implicated in intercellular communication in the tumor microenvironment,suppressing anti-tumor immunity and preparing the metastatic niche for progression.A significant question in the field is how the release and composition of tumor exosomes are regulated.In this perspective article,we explore how physical factors such as geometry and tissue mechanics regulate cell cortical tension to influence exosome production by co-opting the biophysics as well as the signaling dynamics of intracellular trafficking pathways and how these exosomes contribute to the suppression of anti-tumor immunity and promote metastasis.We describe a multiscale modeling approach whose impact goes beyond the fundamental investigation of specific cellular processes toward actual clinical translation.Exosomal mechanisms are critical to developing and approving liquid biopsy technologies,poised to transform future non-invasive,longitudinal profiling of evolving tumors and resistance to cancer therapies to bring us one step closer to the promise of personalized medicine.
基金supported by the National Natural Science Foundation of China(Grant No.51775197)the Science and Technology Planning Project of Guangdong Province(Grant No.2018A050506007)the Guangzhou Science and Technology Program Project(Grant No.201704020090)。
文摘Latest advances have witnessed the laser induction process on polyimide(PI)films for the formation of porous graphene.Herein,a fully converted graphene film was prepared by Nd:YAG laser scribing a gelatin coated PI film.It was found that the gelatin played the role of"shield"well in absorbing intense laser impact and benefit for the surface morphology modulation.Laser treatment lower than a critical fluence point of~4.00 J mm^(-2) contributed to a crater-like surface morphology due to the dispersed nature of Nd:YAG laser beam.By tuning laser fluence above the threshold,carbonized surface turned into continuous morphology.A fluid dynamics process accompanied by outgassing occurred during the carbonization,and the surface morphology gradually varied from stretched droplets to porous strips and finally to amorphous porous structures.The morphology evolution in combination with surface chemistry is responsible for the significant wettability transition from superhydrophobic to superhydrophilic,and a Janus superhydrophobic/superhydrophilic surface wettability was achieved under a laser fluence of~8.00 J mm^(-2).Eventually,microsupercapacitors(MSCs)were fabricated to show the great potential of our prepared graphene in flexible electronics.
