The early stages of crystallization and occurrence of surface wrinkling were investigated using poly(butadiene)-block-poly(ε-caprolactone)with an ordered lamellar structure.Direct evidence has demonstrated that surfa...The early stages of crystallization and occurrence of surface wrinkling were investigated using poly(butadiene)-block-poly(ε-caprolactone)with an ordered lamellar structure.Direct evidence has demonstrated that surface wrinkling precedes nucleation and crystal growth.This study examined the relationship between surface wrinkling,nucleation,and the formation of crystalline supramolecular structures using atomic force microscopy(AFM)and X-ray scattering measurements.Surface wrinkling is attributed to curving induced by accumulated stresses,including residual stress from the sample preparation and thermal stress during cooling.These stresses cause large-scale material flow and corresponding changes in the molecular conformations,potentially reducing the nucleation barrier.This hypothesis is supported by the rapid crystal growth observed following the spread of surface wrinkles.Additionally,the surface curving of the polymer thin film creates local minima of the free energy,facilitating nucleation.The nuclei subsequently grow into crystalline supramolecular structures by incorporating polymer molecules from the melt.This mechanism highlights the role of localized structural inhomogeneity in the early stages of crystallization and provides new insights into structure formation processes.展开更多
A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)...A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)and 10 wt%hydroxypropyl cellulose(HPC)has been reported.The wrinkling system exhibited significant optical tuning from transparent to opaque states with 50%changes in transmittance,which was achieved through the dual mechanical modes of pre-stretching and releasing processes or bending.Upon exposure to ethanol vapor or a re-flattening process,wrinkles can be erased,yielding a transparent state.Consequently,the wrinkling system could be reversibly switched between transparency and opacity for 1000 cycles with marginal changes in the optical performance.Owing to the insolubility of PVB in water,the wrinkling patterns exhibited excellent durability in high-humidity environments(relative humidity(RH)=99%).Furthermore,the smart encryption device is also demonstrated via mechano-controlled surface topography by patterning the wrinkling system,suggesting potential applications of the designed structure in smart windows,anti-counterfeiting,dynamic display,optical information encryption,and rewritable surfaces.展开更多
In this paper,we present a simple method by combining surface wrinkling and template replication to create a series of hierarchical structures on polydimethylsiloxane（PDMS） elastomer.The primary stable lined pattern...In this paper,we present a simple method by combining surface wrinkling and template replication to create a series of hierarchical structures on polydimethylsiloxane（PDMS） elastomer.The primary stable lined patterns are formed by duplicating commercialized compact disk and digital versatile disk with PDMS.The secondary microscale patterns are from surface wrinkling,which is elicited by oxygen plasma（OP） treatment of the prestrained PDMS stamp followed with the prestrain release.By systematically varying the OP exposure duration,the prestrain,and the angle（θ） between the primary pattern orientation and the prestrain direction,we obtain highly ordered well-organized composite patterns from different patterning techniques and with different length scales and mechanical stabilities.展开更多
The surface wrinkled structures of materials endow them with various properties,such as hydrophilicity/hydrophobicity,adhesion,large specific surface area,etc.,which have been applied in self-cleaning surfaces,strong ...The surface wrinkled structures of materials endow them with various properties,such as hydrophilicity/hydrophobicity,adhesion,large specific surface area,etc.,which have been applied in self-cleaning surfaces,strong adhesives,ultra-sensitive sensors,etc.However,traditional wrinkled surfaces with single wrinkled structures cannot meet the demand for intelligent regulation,making the widespread application rather challenging.Recently,stimuli-responsive wrinkled surfaces,which are capable of reversibly regulating wrinkled structures(amplitude,period,etc.),have been developed to broaden their applications.Here,an overview of stimuli-responsive wrinkled surfaces is provided.First,the mechanism and design principle of surface wrinkled structures based on film/substrate bilayer systems are comprehensively analyzed.Subsequently,the latest advancements in the preparation and application of stimuli-responsive wrinkled surfaces are presented from the perspective of types of external stimuli(light,temperature,pH,humidity,solvent,and strain).Finally,the current challenges and future prospects of the stimuli-responsive wrinkled surfaces are illustrated.This review provides some insights and valuable references for the rational design of stimuli-responsive wrinkled surfaces.展开更多
The performance of microwave-assisted spark ignition(MAI)under exhaust gas recirculation conditions was explored with CO_(2)-diluted CH-air premixed spherical flames in a constant volume combustion chamber.The flame k...The performance of microwave-assisted spark ignition(MAI)under exhaust gas recirculation conditions was explored with CO_(2)-diluted CH-air premixed spherical flames in a constant volume combustion chamber.The flame kernel radius at 5 ms after spark started was selected to evaluate the property of MAI for CO_(2)dilution ratio of 0-20%and equivalence ratio of 0.6-1.4 with 1 kHz microwave pulse repetition frequency under 0.2 MPa ambient pressure.The results showed that the addition of microwave induced some wrinkles on the flame surface and strongly deformed the flame.MAI expanded the limit of CO_(2)dilution ratio to 16%with an equivalence ratio of 0.75,in which case the spark only(SI)failed to ignite the mixture.With the CO_(2)dilution ratio increasing,the wrinkles induced by microwave pulses decreased apparently,and the enhancement value of MAI peaked at 4%CO_(2)dilution ratio.The effect of microwave was considered in two aspects,namely,reaction kinetics and thermal effect,which shows a“trade-off”as CO_(2)dilution ratio rose.With 8%volume of CO_(2)added,the flammable interval(equivalence ratio 0.6-1.2)of mixture in SI mode shrunk,and MAI can maintain a flammable interval consistency with the case that no CO_(2)was added.展开更多
We reported a facile and bio-inspired strategy for obtaining antireflective （AR） coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different mo...We reported a facile and bio-inspired strategy for obtaining antireflective （AR） coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different morphologies were generated spontaneously on the surface of coating during photo-cross- linking, which enables the photo-curing coating can decrease reflection. The resulting photo-curing coating exhibits a high transmittance over 90% and low reflection below 5% ～ 8%, with an efficiency anti- reflection of 4% ～ 7%; compared to the flat blank coating. The successful application of these AR coatings with wrinkles pattern to encapsulate the thin film solar cells results in appreciable photovoltaic performance improvement of more than 4% ～ 8%, which benefits from the decrease of the light reflection and increase of optical paths in the photoactive layer by the introduction of wrinkling pattern. Furthermore, the efficiency improvements of the solar cells are more obvious, with a remarkable increase of 8.5%, at oblique light incident angle than that with vertical light incident angle展开更多
Durable superamphiphobic surfaces are highly desired for real-world applications such as self-cleaning,anti-fouling,personal protection,and functional sportswear.However,challenges still exist in constructing robust s...Durable superamphiphobic surfaces are highly desired for real-world applications such as self-cleaning,anti-fouling,personal protection,and functional sportswear.However,challenges still exist in constructing robust superamphiphobic surfaces by using short-fluorinated polymers as one of the promising alternatives for environmentally unfriendly long perfluorinated side-chain polymers.Hierarchical patterns on biological skins endow the creatures with a specific surface for survival.Here,a facile strategy was proposed to generate hierarchical wrinkles for ultradurable superamphiphobic fabrics by simulating the deformation adaptability of snakeskin.Snake-like hierarchical winkling was constructed by the infusion of reactive perfluorooctyltriethoxysilane(FOS)in a wet chemical plus vapor polymerization process.Upon the infusion of FOS,the mismatch of shrinkage caused by gradient crosslinking leads to the formation of a soft wrinkled poly(perfluorooctyl trieth-oxysilane)(poly-FOS)surface.Such a snakeskin-like hierarchical wrinkled surface and high fluorine density of poly-FOS endowed the treated superamphiphobic fabrics with high water resistance(contact angle 169°),castor oil resistance(154°),and extraordinary durability(withstanding 100 standard laundries,15,000 rubbing cycles and strong acid and alkali solu-tions).Moreover,a superamphiphobic surface can be formed on various substrates,including fabric,wood,paper,and glass.This work thus gives new insights into the environmentally friendly manufacture of ultradurable superamphiphobic fabrics.展开更多
Stimulus-sensitive surfaces with tunable morphologies exhibit a wide range of applications in the fields of surface science and engineering.Herein,a cost-effective yet practical strategy is proposed to fabricate photo...Stimulus-sensitive surfaces with tunable morphologies exhibit a wide range of applications in the fields of surface science and engineering.Herein,a cost-effective yet practical strategy is proposed to fabricate photo-sensitive patterning surface on film/substrate wrinkle system based on an azo-containing polyblend.By manipulating the stress field of the bilayer system globally and/or locally upon the stress relaxation triggered by the reversible cis-trans isomerization of the azobenzene,heating/cooling triggered surface wrinkles on the polyblend films could be tailor-made with visible-light-irradiation.Notably,upon selective photo-irradiation,bespoke surface patterns may be cyclically generated or eliminated,allowing these reconfigurable patterned polyblend surfaces to be used as rewritable information storage media for non-ink printing.The as-prepared photo-printed information patterns with high-resolution are shown to be rewritable for multiple cycles and legible for over 90 d in dark ambient conditions.This study not only provides a versatile strategy for flourishing the stimulus-sensitive systems,but also sheds light on the stress relaxation-triggered morphological evolution of the wrinkling polyblend films.展开更多
The self-assembly of surface-order structures based on the surface wrinkling of stiff film-compliant substrate structures(SFCS)is potentially useful in the fabrication of functional devices,the manufacture of superhyd...The self-assembly of surface-order structures based on the surface wrinkling of stiff film-compliant substrate structures(SFCS)is potentially useful in the fabrication of functional devices,the manufacture of superhydrophobic or self-cleaning surfaces,and so on.Due to the influence of the intrinsic characteristic length(g),the surface wrinkling behavior of SFCS at the micro scale is different from that at the macro scale.In this work,based on the strain gradient theory,a trans-scale surface wrinkling model for SFCS is established.First,the effectiveness of this model is verified by previous experiments.Then,based on the model and dimensional analysis,the effect of g on the surface wrinkling behavior is investigated,and the scaling relationship of surface wrinkling of SFCS at different scales is analyzed.The results show that the influence of g cannot be neglected when the film thickness decreases to the one comparable to g.At the micro scale,g will lead to the increase of the critical wrinkling wavelength and load.In addition,the scaling relationship of surface wrinkling at the micro scale will not follow the traditional one.Our study explains the underlying mechanism of the dissimilarity of surface wrinkling behaviors of SFCS at different scales and lays a theoretical foundation for the precise control of surface-order structures.展开更多
基金the National Natural Science Foundation of China(Nos.U2032101 and 11905306)the National Key Research and Development Project of China(No.2022YFB2402602).
文摘The early stages of crystallization and occurrence of surface wrinkling were investigated using poly(butadiene)-block-poly(ε-caprolactone)with an ordered lamellar structure.Direct evidence has demonstrated that surface wrinkling precedes nucleation and crystal growth.This study examined the relationship between surface wrinkling,nucleation,and the formation of crystalline supramolecular structures using atomic force microscopy(AFM)and X-ray scattering measurements.Surface wrinkling is attributed to curving induced by accumulated stresses,including residual stress from the sample preparation and thermal stress during cooling.These stresses cause large-scale material flow and corresponding changes in the molecular conformations,potentially reducing the nucleation barrier.This hypothesis is supported by the rapid crystal growth observed following the spread of surface wrinkles.Additionally,the surface curving of the polymer thin film creates local minima of the free energy,facilitating nucleation.The nuclei subsequently grow into crystalline supramolecular structures by incorporating polymer molecules from the melt.This mechanism highlights the role of localized structural inhomogeneity in the early stages of crystallization and provides new insights into structure formation processes.
基金supported by the Science and Technology Development Fund(FDCT),Macao SAR(No.0149/2022/A),and(No.0046/2024/AFJ)Guangdong Science and Technology Department(No.2023QN10C305)。
文摘A high humidity-resistant,dual mechanical responsive,and reversible mechanochromic wrinkling system based on a VHB 4910-polydimethylsiloxane(PDMS)substrate with a thin film consisting of 90 wt%poly(vinyl butyral)(PVB)and 10 wt%hydroxypropyl cellulose(HPC)has been reported.The wrinkling system exhibited significant optical tuning from transparent to opaque states with 50%changes in transmittance,which was achieved through the dual mechanical modes of pre-stretching and releasing processes or bending.Upon exposure to ethanol vapor or a re-flattening process,wrinkles can be erased,yielding a transparent state.Consequently,the wrinkling system could be reversibly switched between transparency and opacity for 1000 cycles with marginal changes in the optical performance.Owing to the insolubility of PVB in water,the wrinkling patterns exhibited excellent durability in high-humidity environments(relative humidity(RH)=99%).Furthermore,the smart encryption device is also demonstrated via mechano-controlled surface topography by patterning the wrinkling system,suggesting potential applications of the designed structure in smart windows,anti-counterfeiting,dynamic display,optical information encryption,and rewritable surfaces.
基金Financial supports from the Natural Science Foundation of China(Nos.21074090 and 21374076)Tianjin Research Program of Application Foundation and Advanced Technology (No.13JCYBJC17100)
文摘In this paper,we present a simple method by combining surface wrinkling and template replication to create a series of hierarchical structures on polydimethylsiloxane（PDMS） elastomer.The primary stable lined patterns are formed by duplicating commercialized compact disk and digital versatile disk with PDMS.The secondary microscale patterns are from surface wrinkling,which is elicited by oxygen plasma（OP） treatment of the prestrained PDMS stamp followed with the prestrain release.By systematically varying the OP exposure duration,the prestrain,and the angle（θ） between the primary pattern orientation and the prestrain direction,we obtain highly ordered well-organized composite patterns from different patterning techniques and with different length scales and mechanical stabilities.
基金support from the National Natural Science Foundation of China(No.52103299)the science foundation of national key laboratory of science and technology on advanced composites in special environments(No.6142905241301).
文摘The surface wrinkled structures of materials endow them with various properties,such as hydrophilicity/hydrophobicity,adhesion,large specific surface area,etc.,which have been applied in self-cleaning surfaces,strong adhesives,ultra-sensitive sensors,etc.However,traditional wrinkled surfaces with single wrinkled structures cannot meet the demand for intelligent regulation,making the widespread application rather challenging.Recently,stimuli-responsive wrinkled surfaces,which are capable of reversibly regulating wrinkled structures(amplitude,period,etc.),have been developed to broaden their applications.Here,an overview of stimuli-responsive wrinkled surfaces is provided.First,the mechanism and design principle of surface wrinkled structures based on film/substrate bilayer systems are comprehensively analyzed.Subsequently,the latest advancements in the preparation and application of stimuli-responsive wrinkled surfaces are presented from the perspective of types of external stimuli(light,temperature,pH,humidity,solvent,and strain).Finally,the current challenges and future prospects of the stimuli-responsive wrinkled surfaces are illustrated.This review provides some insights and valuable references for the rational design of stimuli-responsive wrinkled surfaces.
基金Project(KF2028)supported by the State key Laboratory of Automotive Safety and Energy,ChinaProject(KF2028)supported by the State Key Laboratory of Automotive Safety and Energy,China。
文摘The performance of microwave-assisted spark ignition(MAI)under exhaust gas recirculation conditions was explored with CO_(2)-diluted CH-air premixed spherical flames in a constant volume combustion chamber.The flame kernel radius at 5 ms after spark started was selected to evaluate the property of MAI for CO_(2)dilution ratio of 0-20%and equivalence ratio of 0.6-1.4 with 1 kHz microwave pulse repetition frequency under 0.2 MPa ambient pressure.The results showed that the addition of microwave induced some wrinkles on the flame surface and strongly deformed the flame.MAI expanded the limit of CO_(2)dilution ratio to 16%with an equivalence ratio of 0.75,in which case the spark only(SI)failed to ignite the mixture.With the CO_(2)dilution ratio increasing,the wrinkles induced by microwave pulses decreased apparently,and the enhancement value of MAI peaked at 4%CO_(2)dilution ratio.The effect of microwave was considered in two aspects,namely,reaction kinetics and thermal effect,which shows a“trade-off”as CO_(2)dilution ratio rose.With 8%volume of CO_(2)added,the flammable interval(equivalence ratio 0.6-1.2)of mixture in SI mode shrunk,and MAI can maintain a flammable interval consistency with the case that no CO_(2)was added.
基金the National Natural Science Foundation of China (Nos. 21522403, 51373098)the National Basic Research Program (No. 2013CB834506)+1 种基金Education Commission of Shanghai Municipal Government (No. 15SG13)IFPM 2016B002 of Shanghai Jiao Tong University & Affiliated Sixth People’s Hospital South Campus for their financial support
文摘We reported a facile and bio-inspired strategy for obtaining antireflective （AR） coating through polymerization-induced self-wrinkling. Upon irradiation of light, the complex wrinkle micro-patterns with different morphologies were generated spontaneously on the surface of coating during photo-cross- linking, which enables the photo-curing coating can decrease reflection. The resulting photo-curing coating exhibits a high transmittance over 90% and low reflection below 5% ～ 8%, with an efficiency anti- reflection of 4% ～ 7%; compared to the flat blank coating. The successful application of these AR coatings with wrinkles pattern to encapsulate the thin film solar cells results in appreciable photovoltaic performance improvement of more than 4% ～ 8%, which benefits from the decrease of the light reflection and increase of optical paths in the photoactive layer by the introduction of wrinkling pattern. Furthermore, the efficiency improvements of the solar cells are more obvious, with a remarkable increase of 8.5%, at oblique light incident angle than that with vertical light incident angle
基金support of the National Natural Science Foundation of China(52073046,51873036,51673039,and 52103106)the Program of Shanghai Academic Leader(21XD1420200)+1 种基金the Chang Jiang Scholar Program(Q2019152)the Shanghai Shuguang Program(19SG28).
文摘Durable superamphiphobic surfaces are highly desired for real-world applications such as self-cleaning,anti-fouling,personal protection,and functional sportswear.However,challenges still exist in constructing robust superamphiphobic surfaces by using short-fluorinated polymers as one of the promising alternatives for environmentally unfriendly long perfluorinated side-chain polymers.Hierarchical patterns on biological skins endow the creatures with a specific surface for survival.Here,a facile strategy was proposed to generate hierarchical wrinkles for ultradurable superamphiphobic fabrics by simulating the deformation adaptability of snakeskin.Snake-like hierarchical winkling was constructed by the infusion of reactive perfluorooctyltriethoxysilane(FOS)in a wet chemical plus vapor polymerization process.Upon the infusion of FOS,the mismatch of shrinkage caused by gradient crosslinking leads to the formation of a soft wrinkled poly(perfluorooctyl trieth-oxysilane)(poly-FOS)surface.Such a snakeskin-like hierarchical wrinkled surface and high fluorine density of poly-FOS endowed the treated superamphiphobic fabrics with high water resistance(contact angle 169°),castor oil resistance(154°),and extraordinary durability(withstanding 100 standard laundries,15,000 rubbing cycles and strong acid and alkali solu-tions).Moreover,a superamphiphobic surface can be formed on various substrates,including fabric,wood,paper,and glass.This work thus gives new insights into the environmentally friendly manufacture of ultradurable superamphiphobic fabrics.
基金supports from the National Natural Science Foundation of China (Nos.21704033,52173168)the Natural Science Foundation of Shandong Province (Nos.ZR2020LFG009,SZR1946)the China Postdoctoral Science Foundation (No.2019M662441).
文摘Stimulus-sensitive surfaces with tunable morphologies exhibit a wide range of applications in the fields of surface science and engineering.Herein,a cost-effective yet practical strategy is proposed to fabricate photo-sensitive patterning surface on film/substrate wrinkle system based on an azo-containing polyblend.By manipulating the stress field of the bilayer system globally and/or locally upon the stress relaxation triggered by the reversible cis-trans isomerization of the azobenzene,heating/cooling triggered surface wrinkles on the polyblend films could be tailor-made with visible-light-irradiation.Notably,upon selective photo-irradiation,bespoke surface patterns may be cyclically generated or eliminated,allowing these reconfigurable patterned polyblend surfaces to be used as rewritable information storage media for non-ink printing.The as-prepared photo-printed information patterns with high-resolution are shown to be rewritable for multiple cycles and legible for over 90 d in dark ambient conditions.This study not only provides a versatile strategy for flourishing the stimulus-sensitive systems,but also sheds light on the stress relaxation-triggered morphological evolution of the wrinkling polyblend films.
基金supported by the Postdoctoral Science Foundation of China for Innovative Talents(Grant No.BX2022008)the National Natural Science Foundation of China(Grant Nos.12202007,11890681,12032001 and 11521202)。
文摘The self-assembly of surface-order structures based on the surface wrinkling of stiff film-compliant substrate structures(SFCS)is potentially useful in the fabrication of functional devices,the manufacture of superhydrophobic or self-cleaning surfaces,and so on.Due to the influence of the intrinsic characteristic length(g),the surface wrinkling behavior of SFCS at the micro scale is different from that at the macro scale.In this work,based on the strain gradient theory,a trans-scale surface wrinkling model for SFCS is established.First,the effectiveness of this model is verified by previous experiments.Then,based on the model and dimensional analysis,the effect of g on the surface wrinkling behavior is investigated,and the scaling relationship of surface wrinkling of SFCS at different scales is analyzed.The results show that the influence of g cannot be neglected when the film thickness decreases to the one comparable to g.At the micro scale,g will lead to the increase of the critical wrinkling wavelength and load.In addition,the scaling relationship of surface wrinkling at the micro scale will not follow the traditional one.Our study explains the underlying mechanism of the dissimilarity of surface wrinkling behaviors of SFCS at different scales and lays a theoretical foundation for the precise control of surface-order structures.
基金the financial support from the National Key Research and Development Program of China (2023YFB3608904)the National Natural Science Foundation of China (21835003)+4 种基金the Natural Science Research Start-Up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications (NY222103)the Natural Science Foundation of Jiangsu Province (BE2019120)the Foundation of Key Laboratory of Flexible Electronics of Zhejiang Province (2023FE002)the Program for Jiangsu Specially-Appointed Professor (RK030STP15001)the Leading Talent of Technological Innovation of National Ten-Thousands Talents Program of China
