Architectural Effects in the Phase Formation and Miscibility of SCLCPs Prepared by ATRP

与基于传统非介晶单体的聚合物相比，侧链液晶聚合物(SCLCP)的结构对性能的影响几乎没有被研究过。合成环状和支化的SCPCP是为了确定支化程度是否会阻碍聚合物形成液晶相的能力，并研究每个重复单元中是否存在长的介晶侧链影响其任何溶液和固态性质，从而使SCLCP的支化程度可能看起来比其标称值更大。特别是，寻求一种理想的体系结构，用于产生具有异常流动的中间相的SCLCP，从而可以识别新的应用，或者为了与LMMLCs竞争将受益于聚合物结构完整性的应用。这些不同的结构也需要用来研究由非活性聚合合成的SCLCP经常表现出的广泛相变的来源。提出了一种新的化学方法来合成第一个环状聚丙烯酸酯和第一个超支化聚丙烯酸酯，它们在化学上类似于直链聚丙烯酸酯；超支化聚合物将包含一个酯基，沿着聚合物主干每隔一个碳原子连接一个酯基，一个不含引发剂的烷基酸酯作为自由侧链连接。所有提出的体系结构对于SCLCP领域来说都是新的。聚合物的溶液行为将通过光散射测量和凝胶渗透色谱(GPC)作为分子量的函数进行研究。均聚物的热致行为将通过DSC、偏光显微镜和可能的X射线衍射来确定，作为分子量和支化程度的函数。偏振光学显微镜还将用于定性确定支化程度如何影响聚合物的动力学，这将与每个体系结构的介原、间隔基、支化点和/或聚合物主干中特定碳的13C-核磁共振T1C自旋晶格弛豫时间相关联。建筑混合物成分的空间分布将通过磁共振成像来表征。拟议的研究是一个多学科项目，将培训研究生和博士后研究人员，包括至少两名女性，在有机、聚合物和物理化学方面。本科生可以通过REU暑期补习册在研究生的指导下在暑期几个月做出贡献。所有参与者将定期在小组会议和ACS和Gordon会议上介绍他们的工作。学生和博士后研究人员将学习如何使用Schlenk Line合成技术，以及如何使用NMR、GPC、DSC、偏振光学显微镜和光散射来表征他们的聚合物、前体和共混物。那些从事链转移研究的学生还将学习如何使用高真空线进行动力学测量。如果阿克伦大学的仪器提议获得成功，这项工作还可通过购置核磁共振成像仪器，帮助改善阿克伦大学的基础设施。

In contrast to polymers based on conventional, non-mesogenic monomers, the effect of architecture on the properties of side-chain liquid crystalline polymers (SCLCPs) has barely been investigated. The synthesis of cyclic and branched SCPCPs is proposed in order to determine if high degrees of branching hinders the ability of the polymer to form a liquid crystalline phase, and in order to investigate whether or not the presence of a long mesogenic side chain in every repeat unit influences any of their solution and solid-state properties, such that the SCLCPs might appear to have greater branching than their nominal values. In particular, an ideal architecture is sought for generating SCLCPs with exceptionally fluid mesophases, such that either new applications can be identified or in order to compete with LMMLCs for applications that would benefit from the structural integrity of a polymer. These different architectures are also needed to investigate the source of the broad phase transitions often exhibited by SCLCPs synthesized by non-living polymerizations. New chemistry is proposed to synthesize the first cyclic polyacrylates and the first hyperbranched polyacrylates that are chemically analogous to linear polyacrylates; the hyperbranched polymers will contain an ester group attached to every other carbon atom along the polymer backbone, with a non-initiator-containing alkylester attached as a free side chain. All of the proposed architectures are new to the field of SCLCPs. The solution behavior of the polymers will be investigated by light scattering measurements and GPC as a function of molecular weight. The thermotropic behavior of the homopolymers will be determined as a function of molecular weight and extent of branching by DSC, polarized optical microscopy and possibly X-ray diffraction. Polarized optical microscopy will also be used to qualitatively determine how the extent of branching affects the polymers' dynamics, which will be correlated with the 13C-NMR T1C spin-lattice relaxation times of specific carbons within the mesogen, spacer, branch points and/or polymer backbone of each architecture. The spatial distribution of the components of the architectural blends will be characterized by magnetic resonance imaging.The proposed research is a multidisciplinary project that will train graduate students and postdoctoral researchers, including at least two women, in organic, polymer and physical chemistry. Undergraduate students may contribute through an REU summer supplement during summer months, with mentoring by the graduate students. All participants will present their work routinely at group meetings and ACS and Gordon conferences. Students and postdoctoral researchers will learn how to use Schlenk line synthetic techniques, and how to use NMR, GPC, DSC, polarized optical microscopy and light scattering in order to characterize their polymers, precursors and blends. Those students working on the chain transfer study will also learn how to use a high vacuum line for their kinetic measurements. This work may also contribute to improving the infrastructure of the University of Akron through the acquisition of an NMR imaging instrument if the university instrument proposal is successful.