Investigating the properties of novel poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) hydrogel hollow fiber membranes

Poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) hydrogel hollow fi ber membranes were synthesized by a novel centrifugal-spinning methodology that resulted in new asymmetric wall morphologies, which in turn affected t he mechanical and transport properties. Hollow fiber membranes were formed after polymerizing the comonomers, 2-hydroxyethyl methacrylate and methyl m ethacrylate, in an aqueous system under centrifugal forces. The concentrati on of methyl methacrylate in the comonomer and the concentration of redox i nitiators were investigated for their effects on membrane morphology, water content, Young's modulus, and diffusive transport. Both monomer compositio n and initiator concentration impacted the resulting asymmetric membrane mo rphology, which varied from a macroporous sponge to a microporous gel to a homogeneous gel. The hollow fiber membranes synthesized herein had equilibr ium water contents between 42 and 57%, elastic moduli between 22 and 400 kP a, and effective diffusion coefficients between 10(-7) and 10(-9) cm(2) s(- 1) for vitamin B12 and 10 kD dextran. The significant differences in both t he moduli and the diffusion coefficients exhibited by these hydrogel membra nes reflect differences in their intrinsic microstructures. Synthesis of hy drogel hollow fiber membranes using centrifugal force is a highly dynamic p rocess; the membrane properties can be effectively tailored by controlling phase separation kinetics. These hydrogel hollow fibers are particularly at tractive for soft tissue applications, such as nerve guidance channels, whe re biocompatibility, mechanical strength, and transport properties are dete rminants of device performance in vivo.