Michael F. Richardson

Amphipathic Polymers with Stimuli-Responsive Microdomains for Water Remediation: Binding Studies with P-Cresol

Amphipathic, stimuli-responsive water-soluble polymers have been investigated as potential remediation agents for micellar enhanced ultrafiltration (MEUF). The systems represent divergent architectural types, a triblock ABA copolymer of PEO-PPO-PEO, an n-octylamide modified poly(sodium maleate-alt-ethyl vinyl ether), and the transport protein, bovine serum albumin. Each type exhibits stimuli-dependent microphase separation or domain formation in response to temperature, pH, and/or ionic strength changes. Segmental associations result in hydrophobic clusters resembling those present in small molecule surfactant micelles. The effects of such segmental aggregation on sequestration of a model hydrophobic foulant, p-cresol, have been investigated using equilibrium dialysis. The favorable molar binding values, the large hydrodynamic dimensions of the stable polymer aggregates, and potential reversibility of foulant loading could have commercial utility in high flow rate, multiple-pass remediation processes.

SYNTHESIS CHARACTERIZATION AND REMEDIATION POTENTIAL OF POLYMERIZABLE SURFACTANT MONOMERS OF N,N-DIALLYL-N,N-DIALKYL AMMONIUM CHLORIDE

The amphiphilic polymerizable surfactants N,N-diallyl-N,N-dioctylammonium chloride, N,N-diallyl-N,N-didecylammonium chloride and N,N-diallyl-N,N-didodecylammonium chloride have been synthesized. Experimental techniques including dynamic light scattering, fluorescence spectroscopy, nuclear magnetic resonance, and atomic force microscopy indicate the monomers form large, well-organized structures similar to vesicles of naturally occurring lipids. Studies of the sequestration of a model foulant by the didodecyl monomer revealed a strong interaction with a high degree of binding. The loading of higher amounts of cresol causes a change in the properties of the monomer assemblies indicating the formation of mixed micellar aggregates. The large monomer aggregates are retained by the dialysis membrane and present a potential alternative to small micellar assemblies.