摘要
研究了基于TMPTA双单体体系光致聚合物中各个组分的作用,对比了多种双单体体系的光致聚合物材料。结合单体的扩散运动,研究了不同成膜树脂、活性单体和光引发剂对光致聚合物的作用及影响,优化了材料的配比。同时在聚合物薄膜样品中成功记录信息,证明其具有良好的全息记录与高的分辨率性能。测试了不同曝光强度、不同曝光时间、不同温度下材料的衍射效率等全息参量,表明双单体体系在光强10~15 mW/cm^(2)、时间40~80 s、温度46℃左右的曝光条件下具有较好的衍射效率。该材料体系在记录角度为30°,厚度70μm时,衍射效率高达91.5%,透过率大于95.6%,折射率调制度至2.98×10^(-3),耐高温性能好。该材料制作简便、周期较短、容易保存,作为全息记录介质能够有效记录高分辨率,高衍射效率的全息信息。由于该聚合物的高衍射效率并且稳定性高等特点,该材料更加适合用于全息图和大数据的永久存储。
In recent years,due to the excellent characteristics of photopolymer recording materials such as high diffraction efficiency,high resolution and high signal-to-noise ratio,they have gradually emerged in volume holographic storage,fiber Bragg grating,waveguide,sensing and communication applications,and achieved a lot of significant results.Among them,a large number of acrylate photopolymers with stable performance,many kinds and low price have been studied.However,acrylate photopolymers have some defects,such as large shrinkage,small refractive index modulation and low stability.These problems hinder the expansion and further application of acrylate photopolymers.Based on the above research,the effects of various components in the photopolymer based on TMPTA double monomer system were studied,and a variety of photopolymer materials based on TMPTA double monomer system were compared in this paper.Combined with the diffusion movement of monomers,the effects of different filmforming resins,active monomers and photoinitiators on photopolymers were studied,and the ratio of materials was optimized.In technology,the system does not require solvent wet treatment.Just mix the medicine evenly and inject it into the mold prepared by two specific pieces of transparent glass.The thickness of the sample can be controlled by the gasket between the glasses,so it is easy to make a film with controllable thickness.Finally,bisphenol A epoxy resin and acrylate monomer TMPTA were selected in different double monomer systems.This is because the reaction activity of epoxy resin and acrylate monomer TMPTA is different,and the polymerization rate of TMPTA is much faster.When TMPTA molecules polymerize rapidly at the bright stripes,the epoxy resin is still colloidal and does not react,which is conducive to the diffusion of TMPTA molecules.Therefore,the two monomers can be separated from each other,resulting in a large refractive index difference.The network structure formed after TMPTA polymerization is combined with epoxy group to initiate epoxy group ring opening,and epoxy group is continuously inserted into it to realize chain growth,branching and crosslinking.A highly crosslinked stable structure is formed in the material.The photoinitiator is high reactive orange solid irgacure 784.Under the 532 nm laser,the ground state of irgacure 784 molecule absorbs photons rapidly,transitions to the excited state,and photodissociates.It forms a product state that is very transparent to visible light.In this system,irgacure 784 molecule first isomerized under the irradiation of coherent light to obtain the coordination unsaturated titanium central double free ground state.Then it initiated the free radical polymerization of TMPTA monomer.Finally,the ring opening polymerization of epoxy resin was carried out under the subsequent treatment.The material thus exhibits high stability and low shrinkage.By introducing double photoinitiators,the polymerization rate of active monomers was greatly accelerated,and the photosensitive sensitivity and photosensitive wavelength range of the system were improved.At the same time,the information is successfully recorded in polymer film samples,which proves that it has good holographic recording and high resolution performance.The holographic parameters are tested,which include diffraction efficiency of materials under different exposure intensity,exposure time and temperature.It shows that the double monomer system has better diffraction efficiency at exposure light intensity of 10~15 mW/cm^(2),time of 40~80 s and temperature of 46℃than at the other conditions.The experimental results show that the system with good high temperature resistance manifests that the diffraction efficiency is up to 91.5%and the refractive index is more than 2.98×10^(-3),also,the transmittance is over 95.6%,which is under the conditions of a recording angle of 30°and a thickness of 70μm.After 72 hours of high and low temperature cycling in the test chamber,the diffraction efficiency decreased to 87.2%and the decrease range was 4.7%.The temperature in the box is maintained at 80℃and the humidity is 80 RH.The shrinkage of Bimonomer photopolymer system is only 0.504%.As a holographic recording medium,it can effectively record holographic information with high resolution and high diffraction efficiency.Due to the high diffraction efficiency and high stability of the polymer,the material is more suitable for other applications such as hologram and permanent storage of big data.
作者
康彪
吕画青
刘悠嵘
李绍鑫
郑继红(指导)
KANG Biao;LÜHuaqing;LIU Yourong;LI Shaoxin;ZHENG Jihong(School of Optical-Electrical and Computer Engineering,University of Shanghai Science and Technology,Shanghai 200093,China;Shanghai Key Lab of Modern Optical System,University of Shanghai Science and Technology,Shanghai 200093,China)
出处
《光子学报》
EI
CAS
CSCD
北大核心
2022年第5期365-374,共10页
Acta Photonica Sinica
基金
国家重点研发计划(No.2018YFA0701802)
国家自然科学基金(No.61975122)。
关键词
全息
衍射光学
衍射效率
光致聚合物
全息光存储
Holography
Diffractive optics
Diffraction efficiency
Photopolymer
Holographic optical storage
