Photocontrolled Molecular Recognition for Materials Applications

该提案描述了新分子的发展，这些分子以可逆的方式相互作用，形成对外部刺激的应用做出反应的“智能”材料，通过以有用的方式改变其物理性质。我们在这一领域的研究的长期目标是：1)通过合理改变组成它们的底层分子设计来创造特定的聚合物(塑料、橡胶)材料的性能，2)使用特定的刺激以确定的方式控制材料的性能-具体地说，在本提案中，我们打算使用光和热来可逆地引起我们制造的材料的性能变化(例如，从固体到粘性液体的转换，然后再转换回来)，3)开发实现1)和2)简单且廉价的方法。 在这项提案中，通过计划开发氢键阵列来解决这些长期目标，该阵列以独特的方式使用一类已知的双(杂芳基)偶氮染料的底层骨架。我们发现，这些染料与我们设计的新的互补分子形成了可逆的络合物，其方式类似于DNA双螺旋中核苷酸碱基的序列特异性配对。将这些体系置于紫外光照射下，会导致双(杂芳基)偶氮染料的拓扑结构发生变化，使它们不能(或不能)与互补伙伴相互作用。它们排列的这种变化导致两个分子解离，并最终改变它们主要或部分保持在一起的任何材料的凝聚力。我们计划利用这一现象来创造新的聚合物材料，这些材料具有以下特性：1)光可调的刚性/弹性/可加工性，2)光可控的自我修复能力。预计这项拟议的研究将大大增加可用于控制塑料和橡胶等材料性能的方法目录。这里概述的研究还将有助于培训化学家在学术和工业职业生涯中有用的广泛技能。

The proposal describes the development of new molecules that interact with each other in a reversible manner to form "smart" materials that react to the application of external stimuli by changing their physical properties in useful ways. The long term goals of our research in this area are; 1) the creation of particular polymer (plastics, rubbers) materials properties through rational changes to the underlying molecular designs that compose them, 2) the use of particular stimuli to control the materials properties in defined ways - specifically in this proposal we intend to use light and heat to reversibly induce changes (e.g. switching from a solid to viscous liquid and back again) in the properties of the materials we make, 3) developing ways to achieve 1) and 2) both simply and inexpensively. These long term goals are addressed in this proposal through the planned development of hydrogen bond arrays that use the underlying skeleton of a class of known bis(heteroaryl)azo dyes in a unique way. We have found that these dyes form reversible complexes with new complementary molecules we have designed in a manner analogous to sequence-specific pairing of the nucleobases in the DNA double helix. Subjecting these systems to irradiation with UV light induces a change in the topology of the bis(heteroaryl)azo dyes and renders them less able (or unable) to interact with their complementary partners. This change in their arrangement causes the two molecules to dissociate and will ultimately alter the cohesion of any material that they are responsible, largely or in part, for holding together. We plan on using this phenomenon to create new polymer materials that exhibit properties such as: 1) Phototunable stiffness/elasticity/processability, 2) Photocontrollable self-healing ability. The proposed research is anticipated to add significantly to the catalogue of methods that may be used to control the properties of materials such as plastics and rubbers. The research outlined here will also aid in training chemists in a wide range of skills useful in both academic and industrial careers.