Chemical seeding via propanol plasma pretreatment for improving adhesion and properties of PECVD siloxane coatings on polymers

Abstract

Siloxane coatings, in particular those deposited by plasma processes, find use as mechanical and environmental barriers for plastic substrates. This study highlights that a propanol‐based plasma pretreatment is not limited to only promoting greater adhesion of the siloxane to plastic. The optical and mechanical properties of graded siloxane coatings deposited onto plasma pretreated substrates are noticeably different to those deposited onto a pristine substrate, with the property change dependent on treatment time. Nanomechanical experiments have shown two distinct regions within the coating for the pretreated samples implying the pretreatment alters the seeding of the coating. It is proposed that the propanol plasma yields a substrate/chamber that is rich in hydroxyl groups which are subsequently incorporated into the growing siloxane coating.

Post‐polymerization surface segregation in thin PECVD siloxane films leading to a self‐regenerative effect

“…Given the study is focused on the potential use of PECVD siloxanes as protective coatings for polymeric substrates, the study was performed on polycarbonate (PC) and CR39 (allyl diglycol carbonate). Performing the test on the target substrates is of high importance as the choice of substrate and its treatment can affect the properties of the coating . The substrate plaques used in the test were 70 × 70 mm PC and CR‐39 (allyl diglycol carbonate) with no additives, obtained from the local supplier City Plastics.…”

“…Performing the test on the target substrates is of high importance as the choice of substrate and its treatment can affect the properties of the coating. [17] The substrate plaques used in the test were 70 × 70 mm PC and CR-39 (allyl diglycol carbonate) with no additives, obtained from the local supplier City Plastics. After deposition, all samples were stored at ambient conditions in a Petri dish with no access to light in a temperature controlled laboratory at 21 ± 1°C.…”