Biocompatible poly(N-vinyllactam)-based materials with environmentally-responsive permeability

Biocompatible polymer-based materials whose properties respond to environmental stimuli are of great value in biomedical and biotechnological applications (e.g., controlled release of drugs and sensitive reactants, bioseparations, spontaneous adjusting of flow of liquids including flow control in microfluidic devices). This study describes preparation and properties of biocompatible poly(N-vinyllactam)-based environment responsive composite membranes. The non-charged network N-vinyl lactam polymers form hydrogels that can exhibit swelling and de-swelling behaviour and, thus, regulate porosity of the membrane. The first part of the study has involved investigation of bulk polymerization reactivity of N-vinylcaprolactam (VCL)-based systems. VCL has been combined with up to 20 mol% of N-vinylpyrrolidone (N-vinylbutyrolactam). These synthetic processes have been investigated as thermal polymerizations (with and without a free-radical initiator) and photopolymerizations. Subsequently, the most reactive systems have been used to prepare composite materials by polymerization-modifying borosilicate microfibre membranes. The modified membranes have been characterized by the net mass gain, infrared spectra, and change in permeability in response to changes in ionic strength of the aqueous media. The permeability experiments have been carried out at constant fluxes and the resultant changes in trans-membrane pressure observed. Those membranes that are ionic-strength responsive could potentially be used for bio-separations and other types of biomedical and biotechnological applications.