SELF-ASSEMBLED DISULFIDE-FUNCTIONALIZED AMPHIPHILIC COPOLYMERS ON GOLD

A series of methacrylic lipids was polymerized to form amphiphilic copolymers with various amounts of 2-hydroxyethyl acrylate (HEA) and 2-(methacryloyloxy)ethylmethyl disulfide comonomers. The behavior of these polymeric lipids was investigated in monolayers both at the air-water interface and in self-assembled monolayers on gold supports. The HEA acts as a hydrophilic spacer along the polymer backbone, and improves the ability of the polymer to self-organize into ordered monolayers, while the disulfide groups act as anchors chemisorbed onto the gold surface. A combination of contact angle measurements, surface plasmon spectroscopy, and cyclic voltammetry shows that the amphiphilic copolymer monolayers are swellable in water and thus that a water layer between the support and the lipid membrane is preserved. The barrier properties of the polymer-modified electrode are improved by annealing in water as well as by increasing the spacer length.