Fabrication Of Temperature-sensitive Polymer Membrane And Its Preliminary Drug Release Study

Polymer membrane is widely used in the field of medicine, such as drug deliverysystems, artificial organs, tissue engineering, bio-separation, medical diagnosticequipment, due to its unique functions in selectivity penetration, controlled drug releaseand so on.N-isopropyl acrylamide (NIPAAM) is a kind of temperature-sensitive monomer incommon use. It is water-soluble at room temperature, and has a low critical solutiontemperature (LCST) at32℃, when the outer temperature is higher than the LCST,which is hydrophobic. Otherwise it’s hydrophilic.Two kinds of temperature-sensitive membranes was fabricated via atom transferradical polymerization (ATRP) while NIPAAM was regarded as monomer.(1) Temperature-sensitive membrane consisting of poly(vinylidene fluoride)backbone with quaternary ammonium-functionalized4-vinylbenzyl chloride (QVBC)and N-Isopropyl acrylamide (NIPAAM) side chains were synthesized via atom transferradical polymerization (ATRP).1H NMR spectroscopy and thermal gravimetric analysis(TGA) present the successful “grafting from” method using ATRP method. By adjustingthe amount of QVBC to tuning the length and hydrophilic of copolymers, a series ofanion exchange membranes with a wide range of ion exchange capacity (IEC), wateruptake (Wu) and hydroxide conductivity were prepared. Ionized side chain andnon-ionized main chain prone to phase separation behavior and run through ion conductchannel, endow the membrane with excellent conductivity of hydroxide ions, theconductivity at room temperature can reach up to41mS/cm. It has the potential inmedical applications such as medical facilities, biological engineering.(2) BPPO-g-NIPAAM membrane was fabricated consisiting of BPPOelectrospinning membrane and temperature-sensitive monomer NIPAAM viasurface-initiated activators regenerated by electron transfer polymerization (SI-ARGETATRP). Grafted membrane was characterized by FT-IR spectroscopy and SEM. BSA permeation was studied at different temperatures in pristine and grafting membraneswhile BSA as model drug. It was found that the permeation rate shows greatdiscrepancy, due to the stretch or shrink of grafting chains when the outer temperature isbelow or above the LCST. The grafting membrane reveals significanttemperature-sensitive behavior in drug release. It can be used as carrier of drugcontrolled release.