UV-Curable Antismudge Coatings
Current antismudge coatings that bear nano-pools of a grafted liquid ingredient for dewetting enablement (NP-GLIDE) are cured at high temperatures, which are undesirable for application on heat-sensitive substrates. Reported herein is the development of a NP-GLIDE coating that can be photocured at room temperature. Of the various formulations that have been tested, robust coatings were obtained from one recipe consisting of a photoinitiator, a trifunctional monomer that bears three double bonds, and a graft copolymer. The last bears pendent double bonds and a poly(dimethylsiloxane) (PDMS) side chain as the antismudge agent. Coatings were prepared by casting films from a solution containing these three components and then photolyzing the resultant films.
A systematic study revealed that the liquid sliding property developed on the coating at a lower cross-linking density than that required for ink to contract. Further, retaining the ability to contract ink traces after many writing and erasing cycles was the most demanding of the three antismudge tests. For our optimized formulation, only 5 min of irradiation was required to yield a transparent coating with superior antismudge properties. Moreover, irradiating selected regions and then removing, with a solvent, reagents in the nonirradiated regions can yield a surface with patterned wettability. These advantageous properties of the new photocurable coating facilitate its applications. (Read More)