UV-Nanoimprinting Lithography Photoresists with No Photoinitiator and Low Polymerization Shrinkage

In this work, a photopolymerizable disulfide monomer containing C(aryl)–S, disulfanediyl bis(4,1-phenylene) diacrylate (ADSDA), was designed and synthesized. UV-nanoimprinting lithography photoresists with no photoinitiator and low polymerization shrinkage were then prepared with ADSDA and benzyl methacrylate (BMA). The photoresists with ADSDA exhibited a great photopolymerization capability in the absence of any photoinitiator, and their double bond conversion reached up to 86%. With the increase of ADSDA content in the photoresists, the Young’s modulus, indentation hardness, and thermal stability of the photoresists all increased first, followed by a slight decrease. Remarkably, the photoresists with ADSDA had a very low polymerization shrinkage which dropped to as low as 0.56% because of the “breakage–recombination” reversible reaction of the S–S bond during the photopolymerization process. More significantly, the pattern of the original mold with 212 nm line width and 104 nm height could be accurately duplicated without flaws by the photoresist, which exhibited a prominent pattern transfer property.