Novel super-hydrophilic coatings with enhanced adhesion on polyolefin substrate obtained by gravure deposition of true amphiphilic block co-polymer water dispersions

Abstract

The aim of this study was to produce and characterise durable, high-performance super-hydrophilic anti-drip coatings based on water dispersions of true amphiphilic block copolymers, to be utilised on agricultural films. The performance of coated low density poly(ethylene) (LDPE) samples, obtained by varying both the coating dispersion formulation and process conditions, were evaluated by means of: hot-fog testing; mechanical wear resistance testing; surface free energy measurements; UV–vis spectroscopy, and; scanning electron microscopy. This study clearly demonstrated that durable super-hydrophilic coatings could be successfully deposited onto LDPE using the proposed approach. In this study, the novel coatings showed excellent adhesion on LDPE substrates, exhibiting anti-drip properties after 100 complete abrasion cycles in an in-house developed test. These levels of mechanical wear resistance, as demonstrated by the optimised coatings, are much greater than those previously reported for antifog films on polyolefins. The molecular architecture of the true amphiphilic block copolymers showed them to be responsible for both the antifogging and enhanced adhesion performance of the coated surfaces. It was demonstrated that the new solvent-free, water-based co-polymer solutions developed, offer important advantages over traditional agricultural films in terms of both their initial and long-term performance, thereby, making them attractive for use in agricultural and other industrial applications.