Simultaneous topographic and chemical patterning via imprinting defined nano-reactors†
Simultaneous topographic and chemical patterning has attracted extensive attention in energy harvesting, sensing, and tissue engineering applications. However, it is still challenging to find a universal topographic-chemical patterning method that applies to arbitrary reactions, and offers tunability on the scale of chemical reactions. Herein, we develop a novel strategy to introduce spatially defined ultra-small reactors based on polymer carriers and imprinting lithography to realize simultaneous topographic and chemical patterning. We present two applications to demonstrate the patterning ability of our method, including synthesizing an ultrafine structured layer of photoluminescent Eu(III) complex on polymer substrate, as well as creating a freestanding poly(maleic anyhydride-alt-1-octadecene)-polyvinyl alcohol copolymer nanostructure. Further studies show that chemical reactions at polymer interfaces were confined within zepto-liter to atto-liter spaces, which corresponded to 103 to 106 molecules. The scale of chemical reactions can be readily tuned through varying imprinting conditions such as pattern geometry, imprinting time, etc. Compared to current patterning techniques, our strategy possesses higher chemical flexibility and compatibility, and allows for better control over the chemical reaction. Not only will this method facilitate fundamental studies of diffusion, reaction dynamics and interfacial chemistry, but it is also highly desired for engineering applications including surface modification, conformal coating and nanofabrication.