Fabricating a Silver Soft Mold on a Flexible Substrate for Roll-to-Roll Nanoimprinting

This study presents an efficient method for fabricating a silver soft mold with a three-dimensional (3-D) nanostructure on flexible polyethersulfone (PES) plastic substrates for a roll-to-roll (R2R) nanoimprint process by employing hot embossing in conjunction with inkjet printing. Prior to fabricating the silver soft mold, the researchers in this study used laser interference lithography (LIL) to fabricate the silicon mold of nanopillar arrays with diameters of 146 nm, heights of 201 nm, and pitches of 291 nm. Inkjet printing was used to coat the silver nanoparticle liquid uniformly on a PES substrate with the designed drop space and volume of droplets. By using hot embossing for 210 s, the researchers transferred the nanopillar arrays from the master Si mold to the liquid on the PES substrate. Finally, the silver nanoparticles of nanohole arrays were sintered on the PES by soft baking for 6 h. The results of this study showed that the silver soft mold could effectively transfer the nanostructures to the polymer substrate through the R2R process in various applications such as antireflection devices.