【作者】 潘阳；

【导师】 唐小真；

【作者基本信息】 上海交通大学 ， 材料学， 2009， 博士

【摘要】 非线性光学材料是实现光通讯、光信息处理、光存储、光全息术、光计算的基础,也是目前重要的高技术应用研究之一,在国防、工业、民用等各个领域都有广泛的应用,但由于存在着诸多限制尤其是非线性-透光性的矛盾,限制了该类聚合物的应用研究。而无机高分子聚磷腈类材料具有优异的光学透明性,热稳定性,化学稳定性,良好的可设计性,因而该类聚合物在非线性光学材料方面得到了深入的研究。聚膦腈类材料是主链上以磷氮原子交替排列,侧链为有机取代基的一类新型无机高分子。由于聚二氯膦腈的主链完全不含碳碳键而且没有形成共轭的大π键,因而主链具有很大的柔顺性;主链的光学透明性比较好,从220nm到近红外区域都没有吸收;两侧的氯原子具有很高的化学活性,可以轻松接上各类不同化学性质的取代基,不同取代基的比例也可以轻松调整以使材料表现出各种不同的物理化学性能;侧基和主链有可能发生相互作用,导致非线性效应的增强;可以交联形成网络获得更加优异的性能。它将无机有机分子的优点紧密地结合起来,从而表现出传统高分子无法企及的特殊性能。在总结了前人研究工作的基础上,本文研究制备了一类全新的基于聚膦腈的光折变聚合物材料,并以此为基础,开展了一系列的创新性研究工作。通过采用设计双(多)重电荷转移分子,合成出了一种具有崭新化学结构的生色团中间体。使用核磁共振、红外光谱、元素分析、凝胶渗透色谱等分析手段表征了中间体;使用差示扫描量热、热重分析等手段研究了中间体的热性能,发现中间体具备良好的热稳定性,具有相当高的玻璃化转变温度;使用紫外吸收光谱研究了中间体的光学吸收性能,发现具有良好的光学透明性,证实了这种双(多)重电荷转移分子具备成为优异生色团的潜质。通过亲核取代反应,成功地将生色团中间体接到了膦腈主链上,最后通过后功能化制备得到了一系列含有不同末端化学端基的光折变聚合物,使用核磁共振、红外光谱、元素分析、凝胶渗透色谱等分析手段表征了目标聚合物。聚合物的光致双折射改变率范围在0.4~1.3x10-2,在取得出色的光学非线性的同时,材料的光学透明性也没有下降,最大吸收只有354~375nm,光学吸收彻底消失在425~465nm,与很多非线性光学性能突出的材料相比,得到了数十纳米的蓝移和宽广的光学透明窗口,这对于解决非线性光学材料中长期存在的非线性-光学透明性矛盾是很有益处的;材料的玻璃化转变温度在150~180℃,具有良好的热稳定性和化学稳定性,保证了材料的非线性光学性能在亚稳态下的稳定性。这还是第一例在室温和不加外电场或提前极化的条件下,在混合组分膦腈聚合物中发现光致折射率改变现象。根据以前人们研究的经验,有机材料一般都要在外加电场或提前极化的条件下,才能表现出光折变现象。而在我们合成的聚合物中,在没有满足上述条件的情况下,就能观测到明显的光折变现象,即所谓的“全光光折变效应”。对于这些材料来说,由于外加电场不是必须的,对材料可能的破坏就完全不用考虑了;而且没有外加电场的限制,聚合物的膜就可以做得很厚以提高材料的光折变性能,这也是很有利的。更多还原

【Abstract】 Nonlinear optical (NLO) materials have been widely researched. The development of NLO materials is very rapid in both synthesis and applications. They have been obtained great applications in the fields of national defence, industries and commodities. However, their applications are restricted due to the nonlinearity-transparency trade-off especially. Polyphosphazenes present a number of useful features for practical devices, such as the excellent flexibility of the backbone, high thermal and oxidative stability, optical transparency from 220 nm to the near-IR region. And controlled incorporation of covalently chromophores can be easily accomplished over a broad concentration range. They have been the focus of much recent research.Polyphosphazenes are inorganic-backbone polymers resulting from the repetition of the–P=N- monomer unit and with two side groups linked to the phosphorus atoms. Because the backbone has no–C-C- bonding or conjugatedπbonding, they are flexible; the backbone has good optical transparency. The chlorine atoms are highly reactive and they can be easily replaced by different groups. The ratio of different groups can be easily tailed. The photorefractivity can be enforced due to the intercourse between backbone and side groups and can get better features by forming network polymers. They combine the advantages of organic and inorganic materials and present some unique performance.A series innovative research works have been carried out and based on synthesis of a new type of photorefractive polyphosphazene polymers at the first time. The work is depicted as follows.A new kind of chromophore intermediate that has brand new chemical structure was synthesized by designing multi-dipolar chromophores. The chromophore intermediate was characterized by means of 1H NMR, 31P NMR, FT-IR, UV-Vis, Elemental Analyses, DSC, TGA and GPC. It presents high thermal stability and glass-transition temperature Tg (>120℃), good transparency. The intermediate was proved to be a competitive candidate.The chlorine atoms of backbone can be replaced by chromophore intermediate through nucleophilic substitution. Some photorefractive polymers with different terminal groups are synthesized and characterized by means of 1H NMR, 31P NMR, FT-IR, UV-Vis, Elemental Analyses, DSC, TGA and GPC.Birefringence of the polymers are about 10-2, silimar to that of other materials coming recently. At the same time, the plymers’transparency is good enough: the maximum absorptionλmax are between 354-375nm, the absence of absorption between 425-465. They provide a wide transparent window and dozens of blueshift compared to other materials which have excellent photorefractivity. The polymers’Tg are between150-180℃, which ensure the stability when the polymers are in metastable state. It is the first time that polyphosphazene polymers were observed to present photorefractivity without adscititious electric field or advanced polarization in room temperature. According to previous research, the presentation of organic materials’photorefractivity usually needs adscititious electric field or advanced polarization. These polyphosphazene polymers are a new kind of materials which are called all-optical photorefractive materials. To these materials, possible damage to the materials causing by adscititious electric field or advanced polarization does not need to be considered. Membrane of the polymers could be made thicker to get better performance when there is no restriction of adscititious electric field or advanced polarization.更多还原