Molecular Dynamics Simulation of Polymer Dissolution

THOMPSON, AIDAN P.

Sandia National Laboratories

关键词: Diffusion;    Polymers;    36 Materials Science;    Dissolution;    Microelectronic Circuits;   

DOI  :  10.2172/808631
RP-ID  :  SAND2003-0397
RP-ID  :  AC04-94AL85000
RP-ID  :  808631

美国|英语

来源: UNT Digital Library

【 摘 要 】

In the LIGA process for manufacturing microcomponents, a polymer film is exposed to an x-ray beam passed through a gold pattern. This is followed by the development stage, in which a selective solvent is used to remove the exposed polymer, reproducing the gold pattern in the polymer film. Development is essentially polymer dissolution, a physical process which is not well understood. We have used coarse-grained molecular dynamics simulation to study the early stage of polymer dissolution. In each simulation a film of non-glassy polymer was brought into contact with a layer of solvent. The mutual penetration of the two phases was tracked as a function of time. Several film thicknesses and two different chain lengths were simulated. In all cases, the penetration process conformed to ideal Fickian diffusion. We did not see the formation of a gel layer or other non-ideal effects. Variations in the Fickian diffusivities appeared to be caused primarily by differences in the bulk polymer film density.