Study on recording stability and optical quality of photopolymer based on sulfonated crosslinked polymer binder

Abstract

The objective of the research is to synthesis novel polymer binder with outstanding dimensional stability and manufacture new photopolymer with excellent recording stability and optical quality for holographic application. In this study, a new photopolymers including polymer binder with nanoporous structure based on sulfonated crosslinked ionomer were prepared and investigated their optical performance. The polymer binder was synthesized with three monomers, which were AMPS, HEDA and EHA by UV- curing with benzophenone. After the synthesized polymer binders were purified, whether residual monomer exist or not was identified with $^1H$ NMR and sulfur contents were measured with Elemental analyzer. The nanostructure of the polymer binder, ion cluster, was observed at $q = 0.1~0.4 Å^{-1}$ via SAXS and identified by measuring two $T_g$ via DSC. For the preparation of photopolymer with nano-domain, polymer binder is dipped in photosensitive solution composed of methylene blue (MB) as photosensitizer and triethanolamine (TEA) as initiator together with acrylamide (AA) as monomer. The nanostructure of the photopolymer was also identified with SAXS. The photopolymer was recorded with unslanted geometry at I=20mW/㎠ with linear polarized He-Ne laser beams (8mW) with 633nm wavelength. The laser was split into two beam with an intensity ratio 1:1 by a beam splitter and recorded in θ=15˚ from the normal of glass substrate. The intensities of the diffracted and undiffracted light were measured at diode by blocking one of the writing beams. The photopolymers had different uptake amounts with solvents of photosensitive solution, crosslinking density, uptake temperature, neutralization time and the content of the AMPS. Therefore, photopolymers showed different optical performance such as diffraction efficiency, transmittance and sensitivity. Our new photopolymer exhibited outstanding recording stability due to chemically and physically crosslinked binder and excellent optical ...