Amphipathic Synthetic and Biological Macromolecules in Aqueous Media

Biological and synthetic amphipathic macromolecules are often capable of forming phase-separated microdomains in response to external stimuli, for example pH, ionic strength, shear stress, and temperature. In this manuscript, we discuss the aqueous solution behavior of two synthetic polymers and a biopolymer that possess microstructural features which allow reversible associations. The first synthetic series was prepared by hydrolyzing an octylamide-modified polymer of maleic anhydride [MA] and ethyl vinyl ether [EVE]. Responsiveness to pH has been studied via energy transfer utilizing photophysical probes. The second series of copolymers was synthesized by cyclocopolymerization of N,N-diallyl-N,N-dimethyl ammonium chloride [DADMAC] and 3-(N,N-diallyl-Nmethylammonio)-1-propanesulfonate [DAMAPS]. Electrolyte responsiveness of these novel sulfobetaine copolymers is discussed as a function of composition. The final amphipathic water-soluble polymer is hydrophobin, a fungal protein secreted by Schizophyllum commune. This protein is capable of self-assembly from water onto both hydrophilic and hydrophobic surfaces as demonstrated by contact angle and AFM studies.