Impacts of modifier chemicals on the rates of diffusion in Acrylamide/PVA photopolymer

摘要

Holographic data storage systems, utilising various photopolymer materials as the recording medium, are currently being developed. The photopolymer recording material used in this study is an Acrylamide/PVA based material. In this paper, having determined values for some basic properties of the material such as diffusion of Polyacrylamide and diffusion of water, we now look at chemically modifying the material and experimentally determine the impact. An important material characteristic, which determines the performance of any photopolymer medium, is the spatial frequency response of that material. Previously, applying our Non-local Photo-Polymerisation Driven Diffusion Model, (NPDD), we have discussed the effects on material behaviour of the length of the polymer chains and the rates of diffusion within the material. These parameters have been shown to be important in determining the response of the material. If the average length of the Polyacrylamide chains is shortened, an increase in the diffusion coefficient might be observed. Shorter Polyacrylamide chains should then result in an increase in the materials spatial frequency response, and ultimately in an increase in holographic data storage capacity. One possible method of doing this is to modify the chemical composition of the material to control chain length using, for example, chain transfer agents. The rates of diffusion of the material, both before and after modification of the chemical composition, is compared to determine the impact. Shortening the chains should result in the possibility of creating smaller structures in the photopolymer material.