'Patchy' Nanoparticles from Bottle-brush Polymers

具有表面非均质性或表面“斑块”的粒子作为构建分级纳米系统的基石引起了人们的普遍兴趣。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吸引人，有助于施工过程。聚合物颗粒在纳米尺度上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亚单位组装来实现，这种组装将导致“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亚单位来形成“片状”纳米颗粒。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，这为形成具有独特功能的聚合物纳米材料开辟了新的途径。这项研究将检查这些聚合物的溶液自组装和共同组装，并建立聚合物结构、加工路线和聚集体形态之间的关系。该奖项支持的外展工作将包括本科生参与研究，以及通过以教育为基础的针对K-12学生的拉丁裔外展计划，社区参与。该奖项的主要目标是探索高度接枝聚合物组装的分子和加工决定因素，特别强调纳米颗粒的构建，显示出表面和核心的异质性。可控聚合方法的进步使得合成功能和结构日益复杂的大分子成为可能，例如大分子刷子或瓶刷。与线型两嵌段共聚物相比，人们对影响大分子溶液组装的因素知之甚少。此外，以往的研究表明，聚合物组装的动力学路径是线性嵌段共聚聚合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未被探索。该奖项涉及两个相关目标。第一个目标是研究由两亲性大分子刷状共聚物通过快速组装过程形成纳米颗粒。这将有助于阐明刷状共聚物组装成多分子纳米颗粒的机理，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积木形成复杂的多相纳米系统。这涉及到通过动力学捕获来共同组装具有不同程度化学差异的大分子刷子家族。虽然有许多报道的方法来制备具有表面和/或核心异质性的复合纳米颗粒，但相对柔软和自适应的构建块的聚集可以为进一步的颗粒内修饰提供手段。

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.