Invited presentation at the Gordon Research Conference on Biomaterials: Biocompatibility/Tissue Engineering, July 20- 25, 2003, The Holderness School, Holderness, NH, Conference, Chair: William R Wagner, Vice Chair: Kevin E Healy Gordon Research Conference on Biomaterials: Biocompatibility/Tissue Engineering, July 20-25, 2003 1 Biomimetic Morphologies in Synthetic Polymers via Melt Processing of Co-continuous Immiscible Polymer Blends Kim Phuong N. Le, R. L. Lehman, J. D. Idol, P-M. Ward AMIPP Center, Rutgers University, Piscataway, NJ 08854, K. VanNess, Department of Physics Washington and Lee University, Lexington, VA, USA Abstract PLLA/PMMA polymer composites were studied as a potential biomaterial system in which properties are adjusted by altering the blend ratio and/or the molecular weights of the end members. Blend compositions were prepared by extrusion near the co-continuous point as determined by empirical rheology based immiscibility rules and characterized by several relevant methods. SEM analysis of etched blends shows a columnar co-continuous morphology in which the domain size is approximately 20 – 30 μm. The architecture appears useful for tissue engineering applications either as scaffolding or implant material in which a transient phase is extracted by body fluids, enabling cell and tissue adhesion to the resultant porous surface. DMA and DSC analysis reveal that these blends have two T g s and thus comprise an immiscible composite system, at least in the context of the extrusion environment. In addition to the T g s of the end-members, the DSC spectra also revealed a broad, diffuse T g band centered around 80 o C, which appears to be the marker of a new phase formed in-situ. Biocompatibility factors were studied in a preliminary sense by evaluating bone and muscle cell viability and adhesion and by testing the resilience of the blend elastic modulus in phosphate buffer solution at 37 o C over a 65 day period. Cell viability and adhesion performance was good and elastic modulus was retained over a two month test period.