'Patchy' Nanoparticles from Bottle-brush Polymers

具有表面异质性或表面“斑块”的颗粒作为构建分级纳米系统的构建块受到普遍关注。其中，基于聚合物的纳米颗粒因其更柔软，更动态的特性而特别有吸引力，从而促进了施工过程。在纳米尺度上聚合物颗粒的表面图案化虽然具有挑战性，但可以通过使用具有分子结构的组装亚基来实现，该分子结构将导致“聚集”效应。该奖项允许探索使用具有瓶刷结构的聚合物作为形成“片状”纳米颗粒的亚基。与更传统的线性聚合物不同，人们对具有复杂结构的聚合物的组装行为知之甚少，为形成具有独特功能的聚合物基纳米材料开辟了新的途径。该研究将研究这些聚合物的溶液自组装和共组装，并建立聚合物结构，加工路线和聚集体形态之间的关系。该奖项支持的外联工作将涉及本科生参与研究，并通过针对K-12学生的以教育为基础的拉丁裔外联计划参与社区活动。该奖项的总体目标是探索高度接枝聚合物组装的分子和加工决定因素，特别强调表现出表面和核心异质性的纳米颗粒的构建。可控聚合方法的进展使得能够合成具有增加的功能和结构复杂性的大分子，例如大分子刷或瓶刷。与线性二嵌段共聚物相比，人们对影响大分子溶液组装的因素知之甚少。此外，以前已经表明，聚合物组装的动力学途径是线性嵌段共聚物组装形态的决定因素，而具有更复杂结构的大分子的非平衡行为仍然未被探索。该奖项涉及两个相关的目标。第一个目标是研究通过快速组装过程从两亲性大分子刷共聚物形成纳米颗粒。这将允许阐明刷状共聚物组装成多分子纳米颗粒的机制，并确定组装的绝对时间尺度。第二个目标是研究由两亲性大分子刷构建块形成复杂的异质纳米系统。这涉及通过动力学捕获具有不同程度的化学相异性的大分子刷家族的共组装。虽然有许多报道的方法用于制造表现出表面和/或核异质性的复合纳米颗粒，但相对柔软和自适应的结构单元的聚集可以提供进一步颗粒内修饰的手段。

Particles with surface heterogeneity or surface 'patchiness' are of general interest as building-blocks for the construction of hierarchical nanosystems. Of these, polymer-based nanoparticles are particularly attractive for their softer, more dynamic character, facilitating the construction process. Surface pattering of polymer particles at the nanometer scale, while challenging, can be accomplished through the use of assembling subunits with a molecular architecture that will lead to a 'clustering' effect. This award allows the exploration of the use of polymers with a bottle-brush architecture as subunits for the formation of 'patchy' nanoparticles. Unlike the more traditional linear polymers, considerably less is known about the assembly behavior of polymers with a complex architecture, opening new routes for the formation of polymer-based nanomaterials with unique functions. The research will examine solution self- and co-assembly of these polymers and establish relationships between polymer architecture, processing routes and aggregate morphology. Outreach efforts supported under this award will involve participation of undergraduate students in research, and community involvement through an education-based Latino outreach program targeting K-12 students. The overarching goal of this award is to explore the molecular and processing determinants of assemblies from highly grafted polymers, with particular emphasis on the construction of nanoparticles exhibiting surface and core heterogeneity. Advances in controlled polymerization methods have enabled the synthesis of macromolecules with increasing functional and architectural complexity such as macromolecular brushes or bottle-brushes. In contrast to linear diblock copolymers, little is known about the factors that influence solution assembly of macromolecules. Furthermore, it has been previously shown that kinetic pathways of polymer assembly are determining factors of assembly morphologies from linear block copolymers, whereas the non-equilibrium behavior of macromolecules with more complex architectures remains unexplored. This award addresses two related objectives. First objective is to study nanoparticle formation from amphiphilic macromolecular brush copolymers by a rapid assembly process. This will allow to both elucidate the mechanism of brush copolymer assembly into multi-molecular nanoparticles, and determine absolute timescales of assembly. Second objective is to study the formation of complex heterogeneous nanosystems from amphiphilic macromolecular brush building-blocks. This involves co-assembly of families of macromolecular brushes with varying degrees of chemical dissimilarity through kinetic trapping. While there are many reported methods for fabricating composite nanoparticles exhibiting surface and/or core heterogeneity, clustering of relatively soft and adaptive building-blocks could provide the means for further intra-particle modifications.