Hydration and Viscoelastic Properties of High- and Low-Density Polymer Brushes Using a Quartz-Crystal Microbalance Based on Admittance Analysis (QCM-A)

Abstract

The hydration and viscoelastic properties of synthetic polymer brushes on a substrate were evaluated using a 27 MHz piezoelectric quartz-crystal microbalance based on admittance analysis (QCM-A). The (−ΔFwater)/(−ΔFair) values, which indicate the hydrodynamic water (bound and vibrated water) ratio per unit polymer mass, and the ΔDwater/(−ΔFair) values, which indicate the viscoelastic properties (energy dissipation per mass), were obtained for low- and high-density brushes of each polymer. These values indicated that the low-density polymer chains had different properties, which depended on the chemical features of each polymer. In contrast, these values were similar for the high-density brushes of each polymer, indicating that the polymers were dehydrated and more elastic due to limited space for movement of the chains with the solvent. These mechanical properties are expected to relate to functions such as surface friction and biocompatibility.