Polyelectrolytes with Azobenzene for Self-Assembled Smart Materials

Electrostatic self-assembly of polyelectrolytes containing photoswitchable azo chromophores into multilayers from aqueous solutions is a promising method for the fabrication of thin films containing desired ``smart'' functionalities and/or sensing material. Using various reflection methods (Ellipsometry, SPR, Neutron) and an atomic force microscope (AFM) for force measurements, we show here how the structural, mechanical, and optical properties can depend on the ionization fraction of the assembling polymers. By controlling such film properties as layer thickness, density, kinetics of assembly, adhesion, and elastic response, we are able to custom-design polymer films with a desired architecture and mechanical response. Applications demonstrated will include a light-induced mechanical response for actuation as artificial muscles, and mass transport of the polymers on a Si surface for nanopatterning and holographic information storage.