NANOMECHANICAL CHARACTERIZATION OF TISSUE ENGINEERING POLYMER BLEND SCAFFOLDS

Abstract

Thin polymer films are important for technological advancements in optics, microelectronics, data storage and bioengineering. When we intend to use these films in biological applications such as tissue engineering, they should be able to withstand forces due to cellular growth and not collapse. Films of sub-micron thickness have to be analyzed for their mechanical properties and stability. We attempt to use buckling based metrology (SIEBIMM) to study the elastic modulus of thin films of PCL / PLLA and PCL / PDLA blends, which are used to make tissue engineering scaffolds. Stiff thin films resting on a soft thick substrate undergo buckling when the substrate is released from a strain. Thin films of varying blend compositions were prepared by spin coating, their thickness was measured by Interferometry and Optical and AFM imaging was performed to study the buckling pattern on these films. It was found that this was a phase separated and immiscible blend system and produced a rather complex buckling pattern. It was established that the elastic modulus of such a blend system would be lesser than a homopolymer film of say PS. Comprehensive attempts to detect the actual buckling wavelength across different phases from the complex buckling pattern are made. It will be required to develop a physical model of such complex buckling mechanics and to perform this experiment on a miscible blend system to simplify the analysis of our experiment.