以PQ為光敏感劑的感光高分子製備及其在體積全像資訊儲存上的特性研究

Abstract

本論文主要的研究方向，主要在致力於改善以Phenanthrenequinone (PQ)為光敏感劑的感光高分子材料在體積全像資訊儲存的特性表現，以期能研發具有更佳全像記錄特性及應用性的材料。首先我們製作了不同厚度的PQ/PMMA體積全像記錄塊材，並以不同的光學實驗來探討所製備材料在體積全像資料儲存上的特性，而其中包括光學特性、散射效應、繞射效率和所儲存全像張數之間的關係、多工記錄的曝光時程…等性質，並進一步展示多工儲存的技術，把所儲存的影像加以重建。為了能夠進一步改善PQ/PMMA材料的特性，因此首先我們也必須瞭解PQ/PMMA的記錄機制，利用不同的化學量測來分析PQ溶解於Methyl MethAcrylate（MMA）中的液態樣品及PQ摻雜於PMMA中的固態樣品於照光下的光化學產物，包括紫外光-可見光譜儀（UV-VIS）的穿透光譜、光致發光（Photoluminescence）的光譜量測、質譜儀（Mass spectra）、富利葉轉換的紅外線光譜儀（Fourier transform infrared spectra）、核磁共振光譜（NMR spectra）與凝膠管柱層析（Gel permeation chromatograph）等儀器分析，並提出PQ/PMMA感光高分子的全像記錄機制主要是由PQ與殘留MMA單體在照光情況下進行光化學反應所致，同時我們也利用體積全像材料的定義瞭解到量化的PQ/PMMA動態範圍、特徵曝光能量與敏感度；之後我們以此記錄機制為基礎，藉著不同官能基的quinopne感光劑衍生物以相類似的製程製作出感光高分子塊材，並分析量測不同官能基團與單張不同的記錄光能量之下，對於全像特性的影響；結論也進一步指出這一類的感光劑在推電子基的情況下，全像特性會得到改善，而感光劑摻雜的含量與記錄條件都會影響到整體在全像量測上所顯示的性質。 □接著，我們利用有機金屬化合物與羰基間快速的反應，試著把ZnMA此類有機金屬化合物引入PQ/PMMA中，以期能改善材料的動態範圍與敏感度；利用所製備的感光高分子薄膜為材料並量測了其相關的光學與全像特性；藉由量測不同組成樣品的光穿透度變化，我們得以瞭解當ZnMA與PQ在照光時所主要扮演的角色，實驗的結果指出全像光柵可以記錄於只單純摻雜PQ於PMMA的樣品，但是無法記錄於單純摻雜ZnMA於PMMA的樣品；摻雜較多的量PQ可以提升繞射效率，相對的摻雜較多的ZnMA可以縮短響應時間；因此我們提出PQ作用如光敏感的反應物般，ZnMA則扮演著如催化劑般的角色藉由摻雜的ZnMA；另一方面，摻雜適量ZnMA的樣品到達最大繞射效率所需的時間，從102秒減至59秒（減少了約1.7倍）而繞射效率從0.57%提升到1.62% （增加為2.9倍之多），這樣的結果也指出摻雜有機金屬化合物對於全像特性的改善上有其果效。進一步的，我們藉由材料製程的改良，成功的製備出共摻雜ZnMA與PQ於PMMA的感光高分子體積塊材，其厚度可達數mm；藉由旋轉多工的儲存，我們得以瞭解到所製備材料的體積全像儲存特性，結果指出藉由摻雜ZnMA分子，材料在全像記錄的M/#改進了3倍到達8.8，而敏感度則改進了2.5倍到達1.23 J/cm2。

In this article, we focus on improving characterization of the volume holographic data storage of the photopolymer which use phenanthrenequinone (PQ) as photosensitizer. Firstly, we present an experimental study on the photopolymer poly(methyl methacrylate) doped with PQ molecules. Material characteristics for holographic data storage, including optical characteristics, scattering effect, relation between diffraction efficiency and number of holograms, and exposure schedule for multiple storage, are investigated. An experimental demonstration of multiple storage of digital data pages in a polymer cube is presented. The previous results indicate that the PQ/PMMA can be considered as a promising material for volume holographic data storage application. However, the related characterization of PQ/PMMA such as dynamic range and sensitivity still need to be improved. Hence, we need to find out the recording mechanism of PQ/PMMA. The photo-products in phenanthrenequinone (PQ)-dissolved methyl methacrylate (MMA) liquid samples and PQ-doped poly(methyl methacrylate) (PQ/PMMA) solid photopolymer samples have been analyzed by various chemical measurements, such as UV-Vis transmission spectral, Photoluminecence spectral, Mass spectra, Fourier Transform Infrared spectra, NMR spectra, and Gel Permeation Chromatograph analyses provide us some evidences to recognize the molecular structure of the photoproducts in our PQ/PMMA photopolymers. The results indicate that under light exposure the PQ and MMA form new molecules, mainly an adduct of one PQ molecule with one MMA molecule. In addition, PQ also reacts as photo-initiator to form PMMA oligomers in our samples. The structure change of PQ molecule induces a strong change of the refractive index in material. It provides a mechanism to record phase hologram in our PQ/PMMA photopolymer. Through the paper survey, we know that the organometallic compounds and carbonyl group will form fast chemical reaction under light exposure. Therefore, we try to doped the ZnMA into the PQ/PMMA and characterize the affect to the properties of holographic recording. We report on the fabrication and experimental characteristics of doping Zinc methacrylate (ZnMA) and PQ into a PMMA photopolymer films. We found that holographic gratings can be recorded in pure PQ-doped PMMA, but cannot be recorded in pure ZnMA-doped PMMA. Through diffraction efficiency curves of the prepared samples, with different doped concentration, we proposed that PQ serves as a photosensitive reactant and plays a major role in the formation of phase gratings. ZnMA serves as a sufficient catalyst to accelerate the reaction of PQ with a polymer or ZnMA. The time to reach the maximum diffraction efficiency has been reduced from 102 to 59 (reduced by 1.7 times) and the diffraction efficiency has been raised up from 0.57% to 1.62% (increased by 2.9 times). The holographic characteristic of the photopolymer improved successfully through the doping of ZnMA. Similar concepts can also be applied to other organometallic compounds. Further, we fabricate a novel holographic recording photopolymer named ZnMA/PQ co-doped PMMA, a poly(methyl methacrylate) (PMMA) doped with two elements: zinc methacrylate (ZnMA) and PQ molecules, through the modified thermo-polymerization process with proper temperature condition. The technique for fabricating thick samples of several mm thick is described. Optical and holographic characteristics of the samples have been experimentally investigated. Optical and holographic characteristics of the samples have been experimentally investigated. The holographic recording results show that by adding ZnMA, the dynamic range M/# of sample has been improved by 3 times to 8.8. The sensitivity also has been improved by 2.5 times to 1.23 cm2/J at same time. Significant improvement on volume holographic data storage characterization of PQ/PMMA has been succeeded obtained through adding ZnMA.