title: Adhesive force assisted imprinting of soft solid polymer films by flexible foils.
abstract: We report a simple, rapid, room temperature, pressure-less and large area (approximately cm2) imprinting technique for high fidelity patterning of soft solid polymer films and surfaces like cross-linked polydimethylsiloxane (PDMS) and polyacrylamide (PAA) based hydrogels, both on planar and curved surfaces. The key element of the method is the use of patterned thin flexible foils that readily and rapidly attain a conformal contact with soft (shear modulus < 0.1 MPa) solid surfaces because of adhesive interfacial interactions. The conformal contact is established at all length scales by bending of the foil at scales larger than the feature size, in conjunction with the spontaneous elastic deformations of the surface on the scale of the features. For example, we used the protective aluminum foils of commercial data storage discs, both with or without data stored, for micron and sub-micron pattern transfer. The patterns are made permanent by UV-ozone treatment (for PDMS) or by controlled drying (for hydrogels). Interestingly, elastic contact imprinting of very thin (< 300 nm) films results in about 50% miniaturization of the original foil feature sizes. Complex two dimensional patterns could also be formed even by using a simple one dimensional master by multiple imprinting. The technique can be particularly useful for the bulk nano applications requiring routine fabrication of templates, for example, in the study of confined chemistry phenomena, nanofluidics, bio-MEMS, micro-imprinting, optical coatings and controlled dewetting.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016, India.
authors.forename: Rabibrata
authors.initials: R
authors.lastname: Mukherjee
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Sharma
authors.forename: Manoj
authors.initials: M
authors.lastname: Gonuguntla
authors.forename: Ganesh K
authors.initials: GK
authors.lastname: Patil
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000268:Adhesiveness; D003432:Cross-Linking Reagents / Q000737:chemistry; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004867:Equipment Design; D020100:Hydrogels / Q000737:chemistry; D018625:Microscopy, Atomic Force / Q000379:methods; D053758:Nanoparticles; D049329:Nanostructures / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D010126:Ozone; D011108:Polymers / Q000737:chemistry*; D011312:Pressure; D013499:Surface Properties; D014466:Ultraviolet Rays; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D003432:Cross-Linking Reagents; D004129:Dimethylpolysiloxanes; D020100:Hydrogels; D010126:Ozone; D011108:Polymers; D000099166:Polyacrylamides; C013830:baysilon