Controlled Macromolecular Heterogeneity by ATRP

当前高分子化学合成的努力主要集中在制备结构明确、多分散度低的材料上。所得到的（co）聚合物在加工过程中自组织，但通常也需要一个非常窄的制造机制窗口，以展示所有独特的性质。在过去的几年里，类似的活动是许多合成实验室（包括CMU小组）的主要关注点，并导致了各种可控/活离子体系的成功开发，以及最近的自由基体系。然而，我们认为现在是时候改变合成高分子化学的重点，探索具有可控多相性的材料的合成，而不是不断地追求低多分散性的聚合物。具有可控异质性的聚合物的可用性可能导致高价值应用材料制备的范式转变。将探讨分子非均质性的三个主要因素及其对纳米结构形态的影响，从而研究其宏观性质。它们包括链的均匀性（多分散性）、链的组成（梯度）和链的拓扑结构（分支和交联）。这些参数之间的内在相关性将被研究，潜在的协同作用将被调查。预期的结果可能对科学、教育和我们的社会产生广泛的影响。ATRP中催化剂含量的降低将减少过渡金属催化剂对环境的影响，同时允许制备具有增强性能的材料。宽而可控的分子量分布不仅可以为材料提供新的性能，而且可以放宽加工制度，拓宽加工窗口。非技术概要：本提案讨论了具有可控异质性的聚合物的合成、表征和潜在应用。该提案的几个组成部分可能对科学、教育和我们的社会产生影响。教授本科生和研究生，以及培训博士后和合作小组的访客。CMU小组成员将访问CMU以外的其他实验室，并与CMU其他小组成员一起工作。信息的传播将通过及时的出版物、在（国际）国家会议和CMU网站上的介绍来完成。CMU的CRP联盟成员将被鼓励使用拟议研究中开发的新技术，并在其市场上评估新材料。这些公司将受益于NSF支持的活动所产生的知识。预期的研究结果不仅可以影响合成聚合物化学，还可以影响材料科学，并可能导致具有商业价值的材料的发展，如减震剂，振动和噪声抑制材料，增强性能的表面活性剂，刺激响应水凝胶，纳米多孔材料以及目前无法实现的孔隙形态的潜在膜。

TECHNICAL SUMMARYCurrent synthetic efforts in polymer chemistry are focused on preparation of materials with well-defined structures and low polydispersities. The resulting (co)polymers self-organize during processing but also often require a very narrow fabrication regime window in order to exhibit all unique properties. During the past several years, similar activities were the main of focus of many synthetic laboratories (including CMU group) and resulted in the successful development of various controlled/living ionic and, more recently, radical systems. However, it is believed that it is time to change the focus in synthetic polymer chemistry and explore synthesis of materials with controlled heterogeneities, instead of a constant race for polymers with lower polydispersities. Availability of polymers with controlled heterogeneities may lead to a paradigm shift in preparation of materials for high value applications. Three major elements of molecular heterogeneity will be explored and their effect on nanostructured morphology and consequently, macroscopic properties will be studied. They include chain uniformity (polydispersity), chain composition (gradients) and chain topology (branching and crosslinking). Intrinsic correlations between these parameters will be studied and potential synergistic interactions will be investigated. The anticipated results might have a broad impact on science, education and our society. The diminished level of catalyst in ATRP will reduce the environmental impact of transition metal catalyst and concurrently allow preparation of materials with enhanced properties. Broadened but controlled molecular weight distributions should not only provide materials with new properties but also relax the processing regime and widen the processing window. NON-TECHNICAL SUMMARYThis proposal addresses the synthesis, characterization and potential applications of polymers with controlled heterogeneities. Several components of this proposal can have an impact on science, education and our society. Teaching undergraduate and graduate students, as well as training a postdoctoral fellow and visitors from collaborative groups will take place. Members of CMU group will visit other laboratories outside CMU and will work together with members of other CMU groups. Dissemination of information will be accomplished by timely publications, presentations at (inter)national meetings and at CMU web site. Members of CRP Consortium at CMU will be encouraged to use the new technology developed in the proposed research and evaluate the new materials in their markets. The companies will benefit from knowledge generated by the NSF supported activities. The anticipated research results can impact not only synthetic polymer chemistry but also materials science and may lead to the development of commercially valuable materials such as shock absorbents, vibration and noise dampening materials, surfactants with enhanced properties, stimuli responsive hydrogels, nanoporous materials and potentially membranes with presently unattainable pore morphology.