Probing the Growth Kinetics for the Formation of Uniform 1D Block Copolymer Nanoparticles by Living Crystallization-Driven Self-Assembly
Probing the Growth Kinetics for the Formation of Uniform 1D Block Copolymer Nanoparticles by Living Crystallization-Driven Self-Assembly
复制标题
DOI：
10.1021/acsnano.8b01353
复制
发表时间：
2018-09-01
期刊：
影响因子：
17.1
通讯作者：
Manners, Ian
中科院分区：
文献类型：
--
作者：
Boott, Charlotte E.;Leitao, Erin M.;Manners, Ian
活性结晶驱动自组装 (CDSA) 是一种可结晶嵌段共聚物 (BCP) 和相关两亲物在溶液中生长的方法，最近已成为一种非常有前途且通用的途径，可以控制尺寸和结构来制备均匀的核壳纳米颗粒（胶束）。然而，影响纳米颗粒生长速率的因素尚未得到系统研究。使用透射电子显微镜、小广角 X 射线散射和超分辨率荧光显微镜技术，我们研究了聚（二茂铁基二甲基硅烷）-b-（聚二甲基硅氧烷）（PFS-b-PDMS）的晶种生长动力学，作为使用可结晶发射和生物相容性等的活体 CDSA 系统模型 聚合物。通过改变各种自组装参数，包括浓度、温度、溶剂和 BCP 组成，我们的结果表明，通过降低温度、使用对可结晶 PFS 核形成块较差的溶剂以及增加 PFS 核形成块的长度，可以减少通过活性 CDSA 方法制备纤维状胶束所需的时间。这些结果对于未来各种活体 CDSA 系统的优化具有普遍重要意义。我们的研究还表明，活性 CDSA 的生长动力学并未表现出生长速率对单聚体浓度的一阶依赖性，这与分子单体的活性共价聚合类似。这种差异可能是由 BCP 的链构象效应对种子末端添加和链长分散性的综合影响造成的。
Living crystallization-driven self-assembly (CDSA) is a seeded growth method for crystallizable block copolymers (BCPs) and related amphiphiles in solution and has recently emerged as a highly promising and versatile route to uniform core-shell nanoparticles (micelles) with control of dimensions and architecture. However, the factors that influence the rate of nanoparticle growth have not been systematically studied. Using transmission electron microscopy, small and wide-angle X-ray scattering, and super-resolution fluorescence microscopy techniques, we have investigated the kinetics of the seeded growth of poly(ferrocenyldimethylsilane)-b-(polydimethylsiloxane) (PFS-b-PDMS), as a model living CDSA system for those employing, for example, crystallizable emissive and biocompatible polymers. By altering various self-assembly parameters including concentration, temperature, solvent, and BCP composition our results have established that the time taken to prepare fiber-like micelles via the living CDSA method can be reduced by decreasing temperature, by employing solvents that are poorer for the crystallizable PFS core-forming block, and by increasing the length of the PFS core-forming block. These results are of general importance for the future optimization of a wide variety of living CDSA systems. Our studies also demonstrate that the growth kinetics for living CDSA do not exhibit the first-order dependence of growth rate on unimer concentration anticipated by analogy with living covalent polymerizations of molecular monomers. This difference may be caused by the combined influence of chain conformational effects of the BCP on addition to the seed termini and chain length dispersity.