Micromolding in capillaries of a micro square array was carried out for polystyrene solution in acetone by means of swollen polydimethylsiloxane （PDMS） elastomeric stamp. The resulting micro-cubic poles were isolate...Micromolding in capillaries of a micro square array was carried out for polystyrene solution in acetone by means of swollen polydimethylsiloxane （PDMS） elastomeric stamp. The resulting micro-cubic poles were isolated and separable when the added amount of the polystyrene solution was small. Some special distorting micro-patterns in the micro-square array were observed because of shrinkage resulting from the varying evaporation rate of solvent at different places.展开更多
Microstructures were produced on curved surfaces and micro-protrusions by using direct micromolding with fourthermoplastic polymers. This method is simpler and more convenient than micromolding with liquid prepolymer ...Microstructures were produced on curved surfaces and micro-protrusions by using direct micromolding with fourthermoplastic polymers. This method is simpler and more convenient than micromolding with liquid prepolymer or using theμTM method. By repeated molding, crossed structures were produced with a stamp prepared only with lines. The processingvariables including the softening temperature of the polymers and heating time were discussed. The result shows that theoptimal molding temperature is preferably slightly higher than the melting temperature of the thermoplastic polymers, atwhich polymers are in the critical states of being melted. This method can be applied to many polymers except those with high softening temperatures or high rate of shrinkage upon temperature change.展开更多
An effective procedure was demonstrated to arrange spherical micro-beads into ordered, long, line-shape arrays by means of ＂micromolding in capillaries＂ in soft lithography. Polystyrene （PS） micro-beads with 2-3 m...An effective procedure was demonstrated to arrange spherical micro-beads into ordered, long, line-shape arrays by means of ＂micromolding in capillaries＂ in soft lithography. Polystyrene （PS） micro-beads with 2-3 mm of diameter were used as units and arranged by molding in continuous micro-channels formed by the conformal contact between a glass substrate and an elastomeric stamp with micrometer-scale line patterns on the surface. An aqueous emulsion of PS micro-beads filled these channels by capillary action and was allowed to solidify. The stamp was then removed. The PS micro-beads could be assembled into a string of long line-shape arrays, and the strings were then joined by heating them to their softening temperature. In order to separate the PS micro-bead string from the substrate, the glass was covered with a thin layer of A1 or polymethyl methacrylate. After the A1 layer was dissolved, the string of PS micro-beads would be released. A string of micrometer scale PS beads can be used as a simple and direct ＂model＂ of a real macromolecular chain. It is hopeful to show an analogue with the condensed process of real macromolecules in a mesoscopic scale using the ＂string of PS micro-beads＂.展开更多
A simple,inexpensive direct micromolding method for patterning Au nanocrystal superlattices using a polydimethylsiloxane(PDMS)stamp has been developed.The method involves in situ synthesis of Au(I)dodecanethiolate and...A simple,inexpensive direct micromolding method for patterning Au nanocrystal superlattices using a polydimethylsiloxane(PDMS)stamp has been developed.The method involves in situ synthesis of Au(I)dodecanethiolate and its decomposition leading to Au nanocrystals in the microchannels of the stamp which order themselves to form patterned superlattice stripes,in conformity with the stamp geometry.Owing to its insolubility in common solvents,the dodecanethiolate was made by reacting Au(PPh3)Cl and dodecanethiol in situ inside the microchannels,by injecting first the former solution in toluene at room temperature followed by the thiol solution at 120°C.Annealing the reaction mixture at 250°C,resulted in formation of nanocrystals(with a mean diameter of 7.5 nm)and hexagonal ordering.By using an external pressure while molding,parallel stripes with sub-100 nm widths were obtained.The choice of parameters such as injection temperature of the thiol and concentrations is shown to be important if an ordered superlattice is to be obtained.In addition,these parameters can be varied as a means to control the nanocrystal size.展开更多
An alternative method for SU-8 removal is proposed.Instead of directly using SU-8 microstructure as the electroplating mold,a polydimethysiloxane (PDMS) replica is employed.The metallic micromold insert obtained throu...An alternative method for SU-8 removal is proposed.Instead of directly using SU-8 microstructure as the electroplating mold,a polydimethysiloxane (PDMS) replica is employed.The metallic micromold insert obtained through this method can be easily peeled off from the PDMS replica,meanwhile with high resolution and smooth surfaces.展开更多
基金supported by the National Natural Science Foundation of China(No.20374049)the Specialized Research Pund for the Doctoral Program of Higher Education(20040358018).
文摘Micromolding in capillaries of a micro square array was carried out for polystyrene solution in acetone by means of swollen polydimethylsiloxane （PDMS） elastomeric stamp. The resulting micro-cubic poles were isolated and separable when the added amount of the polystyrene solution was small. Some special distorting micro-patterns in the micro-square array were observed because of shrinkage resulting from the varying evaporation rate of solvent at different places.
基金This work was financially supported by the National Natural Science Foundation of China (No. 20174038).
文摘Microstructures were produced on curved surfaces and micro-protrusions by using direct micromolding with fourthermoplastic polymers. This method is simpler and more convenient than micromolding with liquid prepolymer or using theμTM method. By repeated molding, crossed structures were produced with a stamp prepared only with lines. The processingvariables including the softening temperature of the polymers and heating time were discussed. The result shows that theoptimal molding temperature is preferably slightly higher than the melting temperature of the thermoplastic polymers, atwhich polymers are in the critical states of being melted. This method can be applied to many polymers except those with high softening temperatures or high rate of shrinkage upon temperature change.
基金IV. ACKN0WLEDGMENT This work was supported by the National Natural Science Foundation of China （No.20374049） and the Specialized Research Foundation for the Doctoral Program of Higher Education （20040358018）.
文摘An effective procedure was demonstrated to arrange spherical micro-beads into ordered, long, line-shape arrays by means of ＂micromolding in capillaries＂ in soft lithography. Polystyrene （PS） micro-beads with 2-3 mm of diameter were used as units and arranged by molding in continuous micro-channels formed by the conformal contact between a glass substrate and an elastomeric stamp with micrometer-scale line patterns on the surface. An aqueous emulsion of PS micro-beads filled these channels by capillary action and was allowed to solidify. The stamp was then removed. The PS micro-beads could be assembled into a string of long line-shape arrays, and the strings were then joined by heating them to their softening temperature. In order to separate the PS micro-bead string from the substrate, the glass was covered with a thin layer of A1 or polymethyl methacrylate. After the A1 layer was dissolved, the string of PS micro-beads would be released. A string of micrometer scale PS beads can be used as a simple and direct ＂model＂ of a real macromolecular chain. It is hopeful to show an analogue with the condensed process of real macromolecules in a mesoscopic scale using the ＂string of PS micro-beads＂.
基金Support from the Department of Science and Technology,India is gratefully acknowledgedB.R.thanks council for Scientific and Industrial Research(CSIR),India for financial assistance.
文摘A simple,inexpensive direct micromolding method for patterning Au nanocrystal superlattices using a polydimethylsiloxane(PDMS)stamp has been developed.The method involves in situ synthesis of Au(I)dodecanethiolate and its decomposition leading to Au nanocrystals in the microchannels of the stamp which order themselves to form patterned superlattice stripes,in conformity with the stamp geometry.Owing to its insolubility in common solvents,the dodecanethiolate was made by reacting Au(PPh3)Cl and dodecanethiol in situ inside the microchannels,by injecting first the former solution in toluene at room temperature followed by the thiol solution at 120°C.Annealing the reaction mixture at 250°C,resulted in formation of nanocrystals(with a mean diameter of 7.5 nm)and hexagonal ordering.By using an external pressure while molding,parallel stripes with sub-100 nm widths were obtained.The choice of parameters such as injection temperature of the thiol and concentrations is shown to be important if an ordered superlattice is to be obtained.In addition,these parameters can be varied as a means to control the nanocrystal size.
文摘An alternative method for SU-8 removal is proposed.Instead of directly using SU-8 microstructure as the electroplating mold,a polydimethysiloxane (PDMS) replica is employed.The metallic micromold insert obtained through this method can be easily peeled off from the PDMS replica,meanwhile with high resolution and smooth surfaces.
