Investigating the Effect of Coronal Charge Patterning on the Solution Structure of Amphiphilic Polypeptoid Multiblock Copolymers

凭借这一奖项，路易斯安那州立大学化学系的大分子、超分子和纳米化学项目资助张冬辉教授研究水溶液中两亲性带电嵌段共聚物的结构。两亲性共聚物是同时具有亲水和亲脂肪链段的长链分子。人工合成的化合物，如肥皂、洗涤剂和天然脂蛋白也具有两亲性。该团队研究了这些聚合物中的总电荷如何控制溶液中形成的聚集体的形状。还通过控制水的酸度或pH来研究这些聚集体的刺激响应行为。该项目中制备的聚合物可能会在生物医学领域产生潜在的影响，特别是在智能药物输送领域。这个团队为学生研究人员提供了一个跨学科的培训环境。参加研究项目的学生将获得聚合物合成和表征方面的经验。除了实验室中的研究和指导外，该项目还与正在进行的外展工作相联系。活动包括K-12学校的ChemDemo和You Be The Chemist(YBTC)计划，旨在提高人们对聚合物化学在现代社会中重要性的认识。本研究的重点是了解日冕电荷模式(可电离单体在冠链上的数目和相对位置)对两亲性离子嵌段共聚物(BCP)在稀水溶液中平衡聚集结构的影响。这一知识是通过明智地设计和合成两亲性多肽多嵌段共聚物(MBCP)来获得的，其中冠状电荷模式由冠状链上可电离单体的嵌段长度和顺序控制，并通过结合现有的实验方法来表征其稀溶液结构。中心假设是，在两亲mBCP的冠状嵌段序列中编码的局部静电相互作用通过调节链间堆积、链构象和水在聚集体中的分布来影响平衡聚集体结构。该项目有三个主要目标。第一个目标是通过顺序控制开环聚合的方法合成具有确定的嵌段长度和可电离单体序列的两亲性多肽多嵌段共聚物。在第二个目标中，系统地研究了日冕电荷模式对其在水中溶液自组装所产生的平衡多肽聚集体结构的影响。最后一个目标集中在这些多肽聚集溶液的刺激响应行为上，重点是pH诱导的结构转变。这项研究可能导致在生产具有可控尺寸、几何形状、内部结构和pH响应特性的多肽类纳米结构方面的新的设计规则和可靠的协议。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With this award, the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry is funding Professor Donghui Zhang of the Department of Chemistry at Louisiana State University to investigate the structure of amphiphilic charged block copolymers in aqueous solution. Amphiphilic copolymers are long chain molecules possessing both water-loving and fat-loving segments. Artificial compounds such as soaps and detergents and naturally occurring lipoproteins also have amphiphilic properties. The team studies how the overall charge in these polymers controls the shapes of aggregates formed in solution. Stimuli-responsive behavior of these aggregates is also investigated through control of water acidity or pH. Polymers prepared in this project could have a potential impact in the biomedical area, especially in the field of smart drug delivery. This team provides an interdisciplinary training environment for student researchers. Students who participate in the research program gain experience in polymer synthesis and characterization. Beyond research and mentoring in a laboratory, this project also connects with ongoing outreach efforts. Activities include ChemDemo and You Be the Chemist (YBTC) programs at K-12 schools aimed at increasing the awareness of the importance of polymer chemistry in modern society. This research is focused on understanding the effects of coronal charge patterning (the number and relative position of ionizable monomers on the coronal chains) on the equilibrium aggregate structure of amphiphilic ionic block copolymers (BCPs) in the dilute aqueous solution. This knowledge is attained by judicious design and synthesis of amphiphilic polypeptoid multiblock copolymers (mBCPs) where the coronal charge pattern is controlled by the block length and sequence of ionizable monomers on the coronal chain, and the characterization of their dilute solution structure by a combination of established experimental methods. The central hypothesis is that the local electrostatic interactions encoded in the coronal block sequence of amphiphilic mBCPs influences the equilibrium aggregate structure by modulating the interchain packing, chain conformation, and water distribution in the aggregates. There are three main objectives associated with the project. The first objective focuses on the synthesis of amphiphilic polypeptoid multiblock copolymers having defined block length and sequence of ionizable monomers by sequential controlled ring-opening polymerization methods. In the second objective, the effects of coronal charge pattern on the equilibrium polypeptoid aggregate structures that result from their solution self-assembly in water are systematically investigated. The last objective concentrates on stimuli-responsive behavior of these polypeptoid aggregate solutions, with a strong emphasis on the pH-induced structural transitions. This research could lead to new design rules and reliable protocols in producing polypeptoid-based nanostructures with controlled dimension, geometry, internal structure and pH-responsive characteristics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.