Investigation of Molecular Diffusivity of Photoresist Membrane using Coarse-Grained Molecular Dynamics Simulation

Biocompatible permeable membranes integrated with a microfluidic system, which allow the diffusion of biological molecules with certain molecular weight, are desirable in biomedical applications. This paper reports on a molecular level study of the molecules permeability of epoxy-based chemically-amplified photoresists in MEMS by employing a coarse-grained molecular dynamics simulation. For analyzing diffusion coefficient of molecular in photoresists, Kremer-Grest model (bead-spring model) with an extended angle bending potential was employed. The simulation results show that, with increasing the cross-linked ratio of photoresists, the diffusion coefficient of small molecules in photoresist have larger diffusion coefficient, and which suggests photoresist membrane can be used as permeable membranes with controllable permeability by varying photolithography parameters.