Water-Soluble Holographic Photopolymers for a Sustainable Future—A Review

Holographic photopolymers are subject to extensive studies in recent years because they are low-cost, easy-to-handle, self-processing materials, which have a number of advantages over more traditional holographic materials. The development of low-toxicity photopolymers that are environmentally friendly is highly desirable. The availability of low-toxicity photopolymers will permit the mass production of commercial holograms without harm to the environment. This paper reviews recent developments in low-toxicity water-soluble holographic photopolymers. A novel composition for a water-soluble, low-toxicity photopolymer is described. This new holographic photopolymer has 90% diffraction efficiency in the transmission mode of recording and 50% diffraction efficiency in the reflection mode of recording. This photopolymer has all the necessary holographic characteristics to make it very attractive for commercialisation. The optimised chemical composition of the holographic photopolymer for the production of pressure sensors is addressed. A novel and unique feature of this new material is its high sensitivity to pressure, which can be controlled by changing its composition. Several promising environmentally friendly optical materials are being developed for future holographic applications. The presented review of low-toxicity, water-soluble, holographic photopolymers is the first of its kind. Thus, the importance of the review is twofold—it helps contribute to the development of low-toxicity holographic photopolymers, and it provides insight and new ideas for the development of water-soluble photopolymers for other applications.