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PDMS Stamps (pdm + stamp)
Selected AbstractsSimple Patterning via Adhesion between a Buffered-Oxide Etchant-Treated PDMS Stamp and a SiO2 Substrate,ADVANCED FUNCTIONAL MATERIALS, Issue 13 2007Y.-K. Kim Abstract A very simple polydimethylsiloxane (PDMS) pattern-transfer method is devised, called buffered-oxide etchant (BOE) printing. The mechanism of pattern transfer is investigated, by considering the strong adhesion between the BOE-treated PDMS and the SiO2 substrate. PDMS patterns from a few micrometers to sub-micrometer size are transferred to the SiO2 substrate by just pressing a stamp that has been immersed in BOE solution for a few minutes. The patterned PDMS layers work as perfect physical and chemical passivation layers in the fabrication of metal electrodes and V2O5 nanowire channels, respectively. Interestingly, a second stamping of the BOE-treated PDMS on the SiO2 substrate pre-patterned with metal as well as PDMS results in a selective transfer of the PDMS patterns only to the bare SiO2. In this way, the fabrication of a device structure consisting of two Au electrodes and V2O5 nanowire network channels is possible; non-ohmic semiconducting I,V characteristics, which can be modeled by serially connected percolation, are observed. [source] Soft-Contact Optical Lithography Using Transparent Elastomeric Stamps and Application to Nanopatterned Organic Light-Emitting DevicesADVANCED FUNCTIONAL MATERIALS, Issue 9 2005T.-W. Lee Abstract Conventional photolithography uses rigid photomasks of fused quartz and high-purity silica glass plates covered with patterned microstructures of an opaque material. We introduce new, transparent, elastomeric molds (or stamps) of poly(dimethylsiloxane) (PDMS) that can be employed as photomasks to produce the same resist pattern as the pattern of the recessed (or non-contact) regions of the stamps, in contrast to other reports in the literature[1] of using PDMS masks to generate edge patterns. The exposure dose of the non-contact regions with the photoresist through the PDMS is lower than that of the contact regions. Therefore, we employ a difference in the effective exposure dose between the contact and the non-contact regions through the PDMS stamp to generate the same pattern as the PDMS photomask. The photomasking capability of the PDMS stamps, which is similar to rigid photomasks in conventional photolithography, widens the application boundaries of soft-contact optical lithography and makes the photolithography process and equipment very simple. This soft-contact optical lithography process can be widely used to perform photolithography on flexible substrates, avoiding metal or resist cracks, as it uses soft, conformable, intimate contact with the photoresist without any external pressure. To this end, we demonstrate soft-contact optical lithography on a gold-coated PDMS substrate and utilized the patterned Au/PDMS substrate with feature sizes into the nanometer regime as a top electrode in organic light-emitting diodes that are formed by soft-contact lamination. [source] High-Resolution Contact Printing with Chemically Patterned Flat Stamps Fabricated by Nanoimprint LithographyADVANCED MATERIALS, Issue 27 2009Xuexin Duan Chemically patterned flat stamps provide an effective solution to avoid mechanical stamp-stability problems currently encountered in microcontact printing. A new method is developed to fabricate chemical patterns on a flat PDMS stamp using nanoimprint lithography. Sub-100,nm gold patterns are successfully replicated by these chemically patterned flat PDMS stamps. [source] Thermochemical Patterning of Polymer Thin Films With Tunable Size-Reduction Effects Using Metal-Coated Poly(dimethylsiloxane) StampsADVANCED MATERIALS, Issue 21 2009Fangfang Wang Metal-coated poly(dimethylsiloxane) (PDMS) stamps are treated as parallel microelectrodes to selectively induce thermochemical crosslinking of polymer thin films on Si substrates. Periodical polymer micro- and nanostructures with various size-reduction effects can be achieved by changing the conditions during metal deposition or modifying the surface of the metal-coated PDMS stamp. [source] Force-Free Patterning of Polyelectrolyte Multilayers under Solvent AssistanceMACROMOLECULAR MATERIALS & ENGINEERING, Issue 8 2010Lulu Han Abstract Physical patterns were created on hydrated PSS/PDADMAC multilayers without using external force. A typical process was to put a PDMS stamp onto the wet and swollen multilayers, which were then put into an oven and maintained for a period of time to micromold the multilayers. The influence of molding temperature and time, multilayer thickness, solvent quality, and multilayer compositions on pattern formation were elucidated. Evolution of the patterns from double lines, double strips, and meniscus-shaped ridges to high ridges was observed under all conditions, revealing that this is a universal principle for this process. Finally, patterns on PAA/PAH and PSS/PAH multilayers were also prepared at the optimal conditions, highlighting its wide generality on the multilayer patterning. [source] Stable Non-Covalent Large Area Patterning of Inert Teflon-AF Surface: A New Approach to Multiscale Cell Guidance,ADVANCED ENGINEERING MATERIALS, Issue 6 2010Francesco Valle Micro- and nano-patterning of cell adhesion proteins is demonstrated to direct the growth of neural cells, viz. human neuroblastoma SHSY5Y, at precise positions on a strongly antifouling substrate of technolological interest. We adopt a soft-lithographic approach with oxygen plasma modified PDMS stamps to pattern human laminin on Teflon-AF films. These patterns are based on the interplay of capillary forces within the stamp and non-covalent intermolecular and surface interactions. Remarkably, they remain stable for several days upon cell culture conditions. The fabrication of substrates with adjacent antifouling and adhesion-promoting regions allows us to reach absolute spatial control in the positioning of neuroblastoma cells on the Teflon-AF films. This patterning approach of a technologically-relevant substrate can be of interest in tissue engineering and biosensing. [source] Large-Area Nanoscale Patterning of Functional Materials by Nanomolding in CapillariesADVANCED FUNCTIONAL MATERIALS, Issue 15 2010Xuexin Duan Abstract Within the past years there has been much effort in developing and improving new techniques for the nanoscale patterning of functional materials used in promising applications like nano(opto)electronics. Here a high-resolution soft lithography technique,nanomolding in capillaries (NAMIC),is demonstrated. Composite PDMS stamps with sub-100,nm features are fabricated by nanoimprint lithography to yield nanomolds for NAMIC. NAMIC is used to pattern different functional materials such as fluorescent dyes, proteins, nanoparticles, thermoplastic polymers, and conductive polymers at the nanometer scale over large areas. These results show that NAMIC is a simple, versatile, low-cost, and high-throughput nanopatterning tool. [source] Nanopatterning by an Integrated Process Combining Capillary Force Lithography and Microcontact PrintingADVANCED FUNCTIONAL MATERIALS, Issue 4 2010Xuexin Duan Abstract A novel nanopatterning process was developed by combining capillary force lithography (CFL) and microcontact printing (µCP). Flat polydimethylsiloxane (PDMS) was used as the substrate in CFL, and after chemical functionalization, as the stamp in µCP, which increased the resolution of both methods. The polymer patterns, produced by CFL on a thin polymer film on the flat PDMS substrate, acted as a mask to oxidize the uncovered regions of the PDMS. The chemical patterns were subsequently formed by gas phase evaporation of a fluorinated silane. After removal of the polymer, these stamps were used to transfer thiol inks to a gold substrate by µCP. Gold patterns at a scale of less than 100,nm were successfully replicated by these chemically patterned flat PDMS stamps. [source] Soft-Contact Optical Lithography Using Transparent Elastomeric Stamps and Application to Nanopatterned Organic Light-Emitting DevicesADVANCED FUNCTIONAL MATERIALS, Issue 9 2005T.-W. Lee Abstract Conventional photolithography uses rigid photomasks of fused quartz and high-purity silica glass plates covered with patterned microstructures of an opaque material. We introduce new, transparent, elastomeric molds (or stamps) of poly(dimethylsiloxane) (PDMS) that can be employed as photomasks to produce the same resist pattern as the pattern of the recessed (or non-contact) regions of the stamps, in contrast to other reports in the literature[1] of using PDMS masks to generate edge patterns. The exposure dose of the non-contact regions with the photoresist through the PDMS is lower than that of the contact regions. Therefore, we employ a difference in the effective exposure dose between the contact and the non-contact regions through the PDMS stamp to generate the same pattern as the PDMS photomask. The photomasking capability of the PDMS stamps, which is similar to rigid photomasks in conventional photolithography, widens the application boundaries of soft-contact optical lithography and makes the photolithography process and equipment very simple. This soft-contact optical lithography process can be widely used to perform photolithography on flexible substrates, avoiding metal or resist cracks, as it uses soft, conformable, intimate contact with the photoresist without any external pressure. To this end, we demonstrate soft-contact optical lithography on a gold-coated PDMS substrate and utilized the patterned Au/PDMS substrate with feature sizes into the nanometer regime as a top electrode in organic light-emitting diodes that are formed by soft-contact lamination. [source] High-Resolution Contact Printing with Chemically Patterned Flat Stamps Fabricated by Nanoimprint LithographyADVANCED MATERIALS, Issue 27 2009Xuexin Duan Chemically patterned flat stamps provide an effective solution to avoid mechanical stamp-stability problems currently encountered in microcontact printing. A new method is developed to fabricate chemical patterns on a flat PDMS stamp using nanoimprint lithography. Sub-100,nm gold patterns are successfully replicated by these chemically patterned flat PDMS stamps. [source] |