Self-Assembled Coatings of Stimuli Responsive Polymeric Materials

Switchable control of the interfacial properties of a solid surface, such as surface energy, would be of great significance that is responsive to external stimuli of light, pH or salt. A series of novel amphiphilic polymers, functionalized with azobenzene chromophores monomer for optical applications, and acrylic acid monomer for introducing the self assembly character, were synthesized by preparing a 4-[2-(4-nitrophenyl)diazenyl]phenol dye (NDP) to yield 4-[2-(4-nitrophenyl)diazenyl]phenyl ester (NDP monomer). The NDP monomer and acrylic acid monomer (AA) were polymerized by free radical methods to yield homopolymer PNDP and a series of P(NDP co AA) copolymers with varying chromophores content (mol% from 10 to 50). The prepared copolymers of P(NDP co AA) were used to fabricate SAMu films on glass and silicone substrates by using Layer by Layer sequential assembly. In addition, to the work involving azo polyelectrolyte, thin films based on simple azo electrolytes such as methyl orange were also assembled on glass substrate with the purpose to investigate the effect of external stimuli such as pH or salt addition on their characteristics.