Fabrication and characterization of non-fluoro based transparent easy-clean coating formulations optimized from molecular dynamics simulation

Abstract

Polymer industries are increasingly adopting molecular dynamics simulations for the prediction of targeted properties before going for any material formulation and product development. In this investigation, the impact of co-polymerizing poly(vinyl acetate) (PVAc) with poly(dimethyl siloxane) (PDMS) in developing a suitable easy-cleaning polymeric coating material through both simulation and experimental validation has been reported. PDMS-g-PVAc with different wt.% of PVAc have been molecularly simulated and easy-cleaning ability has been assessed through estimation of properties such as surface energy, substrate adhesion and transparency. Subsequently, the pre-optimized 20 wt.% PDMS-g-PVAc was synthesized experimentally, coated on a substrate and characterized to validate the simulation estimates based on its thermal, optical and surface behavior. Interestingly, properties such as glass transition temperature (Tg), transparency and water contact angle (WCA) and transparency of the optimized PDMS-g-PVAc were found in good accordance with the experimental findings. Additionally, the surface coverage of the methyl (−CH3) groups and acetate (−OCOCH3) groups in PDMS-g-PVAc were found to strongly dictate the surface and interfacial properties as confirmed through surface and Al substrate-interaction energy findings. The simulation protocols suggest reliability by displaying close agreements of simulated density (ρ), solubility parameter (δ), refractive index and WCA of pristine PDMS and PVAc with the reported experimental values. When compared with poly(tetrafluoroethylene) (PTFE), the optimal non-fluoro based graft copolymer was found to exhibit similar or improved thermal degradation, transparency, surface energy and WCA. The significance of this work is believed to broaden the usage of the graft copolymer with 20 wt.% PVAc in PDMS (PDMS-g-PVAc) as an alternative material to fluoropolymers for applied as easy-cleaning coatings.