Intelligent polymeric surfaces through molecular self-assembly

Abstract

Recently, stimuli-responsive surfaces have gained considerable interest among coatings researchers in industry as well as in academe. To date, many switchable surfaces based on such external stimuli as temperature, electricity, pH, and many others have been designed and developed. Environmentally switchable surfaces have been among the most widely studied surfaces since they are known to exhibit smart behavior under external influence. In the present work, we report the synthesis of hydrophobic, hydrophilic, and amphiphilic polyurethane coatings with tethered hydrophilic and/or hydrophobic moieties. These coatings have been characterized and tested for mechanical properties and surface characteristics using such advanced instruments as the scanning probe microscope (SPM), dynamic contact angle analyzer (DCA), adhesion tester, and nanoindenter. The surfaces with tethered hydrophobic or hydrophilic moieties, when immersed in water, showed remarkable changes in the surface topography, hence, their dynamic surface characteristics. The amphiphilic surfaces, containing both hydrophobic and hydrophilic moieties, showed intelligent behavior in response to the external environment. The ability to tailor surfaces with predictable behavior upon exposure to the external environment opens up enormous opportunities for their potential end-use applications.