A facile and versatile route to functional poly(propylene) surfaces via UV-curable coatings

Abstract

A convenient UV-curable coatings assisted surface functionalization strategy is presented to convert commodity Poly(propylene) (PP) films into diverse functional materials. To ensure a covalent integration between PP surface and functional UV-curable coatings, 3-(trimethoxysilyl) propyl acrylate (TMSPA) was functionalized on the surface of oxidized PP film. Two distinct UV-curable coatings differing primarily in the chemical nature of monomers were separately tethered on the surface of TMSPA functionalized PP films. The monomers applied in this study include 1H, 1H,2H,2H-heptadecafluorodecyl acrylate (HFDA) and 2-isocyanatoethyl methacrylate (ICEMA). The use of HFDA as monomer resulted in PP film with fluorinated surface chemical nature, which would be attractive for applications desiring low surface energy, low dielectric constant, low flammability, low refractive index, and superior chemical resistance. Employing ICEMA monomer as part of UV-curable mixture resulted in PP film offering a high density of surface isocyanate groups (-NCO) that could be conveniently conjugated to a variety of amines to give a range of functional surfaces. For proof of concept, the -NCO groups on the surface of PP film were conjugated with amine terminated polyethylene glycol to give PP film that exhibited antifouling nature. In a separate experiment, the surface -NCO groups were conjugated to 2-aminoethanesufonic acid (AESA) to fabricate an anionic PP surface capable of effectively interacting with cationic species. The conjugation of surface -NCO groups with L-lysine imparted pH responsive wettability switching behaviour to the surface of PP film. Finally, poly(ethylene imine) (PEI) was conjugated to surface -NCO groups and the resulting surface PEI moieties were used as reducing and stabilizing agent to synthesize catalytically active gold nanoparticles (AuNPs) confined to the surface of PP film. All the surface functionalization's were fully corroborated by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), water contact angle (WCA) goniometry, and scanning electron microscopy (SEM). Considering the potential for incorporation into the existing industrial processes and resourcefulness of the surface functionalization via UV-curable coatings, we envision that the herein reported strategy holds an excellent potential to transform commodity PP films into a wide range of specialty materials for diverse applications at large scale.