Wrinkling and buckling of nano-films on the compliant substrate are always induced due to thermal deformation mismatch.This paper proposes effective means to control the surface wrinkling of thin film on the compliant...Wrinkling and buckling of nano-films on the compliant substrate are always induced due to thermal deformation mismatch.This paper proposes effective means to control the surface wrinkling of thin film on the compliant substrate,which exploits the curvatures of the curve cracks designed on the stiff film.The procedures of the method are summarized as:1)curve patterns are fabricated on the surface of PDMS(Polydimethylsiloxane)substrate and then the aluminum film with the thickness of several hundred nano-meters is deposited on the substrate;2)the curve patterns are transferred onto the aluminum film and lead to cracking of the film along the curves.The cracking redistributes the stress in the compressed film on the substrate;3)on the concave side of the curve,the wrinkling of the film surface is suppressed to be identified as shielding effect and on the convex side the wrinkling of the film surface is induced to be identified as inductive effect.The shielding and inductive effects make the dis-ordered wrinkling and buckling controllable.This phenomenon provides a potential application in the fabrication of flexible electronic devices.展开更多
In the past two decades,dynamic covalent chemistry has been greatly developed,which is mainly reflected in two aspects:1.new dynamic covalent bonds(DCBs)are continuously discovered;2.various DCBs have been introduced ...In the past two decades,dynamic covalent chemistry has been greatly developed,which is mainly reflected in two aspects:1.new dynamic covalent bonds(DCBs)are continuously discovered;2.various DCBs have been introduced into polymer materials for different functions.These functional polymer materials have brought new opportunities for sustainable development.In this review,we provide an overview of various functions endowed by DCBs in polymer materials,including self-healing,chemical recycling,and shape controlling.Particularly,we pay much attention to the three-dimensional(3D)shape reconfiguration/programming,surface patterning,and reversible actuation.In addition,we also give the current issues,challenges,and opportunities on DCBs-containing materials and point out its developing directions in the future.展开更多
Plant organs are derived from stem cells.Once a leaf primordium initiates growth from the shoot apical meristem（SAM）,it establishes adaxial-abaxial（dorsal-ventral）polarity.This polarity essentially allows the leaf...Plant organs are derived from stem cells.Once a leaf primordium initiates growth from the shoot apical meristem（SAM）,it establishes adaxial-abaxial（dorsal-ventral）polarity.This polarity essentially allows the leaf to become a flat structure with the lamina expanding along the juxtaposition,i.e.,the middle domain,between the adaxial and abaxial domains.展开更多
High refractive index(HRI,n>1.8)photonic structures offer strong light confinement and refractive efficiencies,cover the entire visible spectrum and can be tuned by designing geometric arrayed features.However,its ...High refractive index(HRI,n>1.8)photonic structures offer strong light confinement and refractive efficiencies,cover the entire visible spectrum and can be tuned by designing geometric arrayed features.However,its practical applications are still hindered by the applicability and material limitation of lithography-based micro/nano fabrication approaches.Herein,we demonstrate a fluid-guided printing process for preparing HRI selenium microarrays.The microstructured flexible template is replicated from the diced silicon wafer without any lithography-based methods.When heated above the glass transition temperature,the flow characteristics of selenium endows the structure downsizing and orientation patterning between the target substrate and the template.Near 10 times narrowing selenium microarrays(1.9μm width)are patterned from the non-lithography template(18μm width).HRI selenium microarrays offer high refractive efficiencies and strong optical confinement abilities,which achieve angledependent structurally coloration and polarization.Meanwhile,the color difference can be recognized under the one degree distinction of the angle between incident and refracted light.This printing platform will facilitate HRI optical metasurfaces in a variety of applications,ranging from photonic sensor,polarization modulation to light manipulation.展开更多
基金supported by the National Basic Research Program of China(Grant Nos.2010CB631005 and 2011CB606105)the National Natural Science Foundation of China(Grant Nos.11232008,91216301,11072125 and 11272175)Tsinghua University Initiative Scientific Research Program
文摘Wrinkling and buckling of nano-films on the compliant substrate are always induced due to thermal deformation mismatch.This paper proposes effective means to control the surface wrinkling of thin film on the compliant substrate,which exploits the curvatures of the curve cracks designed on the stiff film.The procedures of the method are summarized as:1)curve patterns are fabricated on the surface of PDMS(Polydimethylsiloxane)substrate and then the aluminum film with the thickness of several hundred nano-meters is deposited on the substrate;2)the curve patterns are transferred onto the aluminum film and lead to cracking of the film along the curves.The cracking redistributes the stress in the compressed film on the substrate;3)on the concave side of the curve,the wrinkling of the film surface is suppressed to be identified as shielding effect and on the convex side the wrinkling of the film surface is induced to be identified as inductive effect.The shielding and inductive effects make the dis-ordered wrinkling and buckling controllable.This phenomenon provides a potential application in the fabrication of flexible electronic devices.
基金financially supported by the National Natural Science Foundation of China(21734006)the Foundation for Innovative Research Group of the National Natural Science Foundation of China(21821001)。
文摘In the past two decades,dynamic covalent chemistry has been greatly developed,which is mainly reflected in two aspects:1.new dynamic covalent bonds(DCBs)are continuously discovered;2.various DCBs have been introduced into polymer materials for different functions.These functional polymer materials have brought new opportunities for sustainable development.In this review,we provide an overview of various functions endowed by DCBs in polymer materials,including self-healing,chemical recycling,and shape controlling.Particularly,we pay much attention to the three-dimensional(3D)shape reconfiguration/programming,surface patterning,and reversible actuation.In addition,we also give the current issues,challenges,and opportunities on DCBs-containing materials and point out its developing directions in the future.
文摘Plant organs are derived from stem cells.Once a leaf primordium initiates growth from the shoot apical meristem（SAM）,it establishes adaxial-abaxial（dorsal-ventral）polarity.This polarity essentially allows the leaf to become a flat structure with the lamina expanding along the juxtaposition,i.e.,the middle domain,between the adaxial and abaxial domains.
基金the National Key R&D Program of China(2018YFA0208501)the National Natural Science Foundation of China(51803217,51773206,91963212,and 51961145102(BRICS Project))+3 种基金the Youth Innovation Promotion Association CAS(2020032)Beijing National Laboratory for Molecular Sciences(BNLMS-CXXM-202005)Russian Foundation for Basic Research(19-52-80036(BRICS Project))K.C.Wong Education Foundation。
文摘High refractive index(HRI,n>1.8)photonic structures offer strong light confinement and refractive efficiencies,cover the entire visible spectrum and can be tuned by designing geometric arrayed features.However,its practical applications are still hindered by the applicability and material limitation of lithography-based micro/nano fabrication approaches.Herein,we demonstrate a fluid-guided printing process for preparing HRI selenium microarrays.The microstructured flexible template is replicated from the diced silicon wafer without any lithography-based methods.When heated above the glass transition temperature,the flow characteristics of selenium endows the structure downsizing and orientation patterning between the target substrate and the template.Near 10 times narrowing selenium microarrays(1.9μm width)are patterned from the non-lithography template(18μm width).HRI selenium microarrays offer high refractive efficiencies and strong optical confinement abilities,which achieve angledependent structurally coloration and polarization.Meanwhile,the color difference can be recognized under the one degree distinction of the angle between incident and refracted light.This printing platform will facilitate HRI optical metasurfaces in a variety of applications,ranging from photonic sensor,polarization modulation to light manipulation.
