UV-curable top coat protection against mechanical abrasion for atomic layer deposition (ALD) thin film barrier coatings

Abstract

It has been demonstrated that atomic layer deposition (ALD) is able to produce high quality, single layer, moisture barrier films on polymer substrates. ALD coatings are extremely conformal, which is ideally suited for creating excellent barriers even on highly imperfect surfaces. ALD by substrate translation enables the production of ultra-barrier films at industrial scales by increasing throughput and lowering cost compared to traditional ALD processing techniques. However, because ALD barrier coatings are thin and deposited on relatively soft polymer substrates, they are particularly susceptible to mechanical abrasion during downstream operations, including rewinding. This study demonstrates that an ultra-violet (UV)-curable, acrylic top coat can be used to preserve the ALD thin film's barrier properties against typical downstream mechanical abrasion. Specifically, 1μm top coat thickness protected 8nm ALD barrier film against typical mechanical abrasion to maintain water vapor transmission rate below an analyzer sensitivity limit, 3×10−3g/(m2·d). In addition, several commercially-viable options exist for scaling-up and integrating overcoat application into roll-to-roll systems.