Centre for Research in Biological Chemistry and Molecular Materials (CIQUS), c Jenaro de la Fuente-Campus Vida, University of Santiago de Compostela (USC), E-15782 Santiago de Compostela, Spain.
Nanotechnology. 2013 Jun 28;24(25):255304. doi: 10.1088/0957-4484/24/25/255304. Epub 2013 May 30.
Thermal annealing was used for the bottom-up fabrication of morphologically controlled gold-block-copolymer (Au-BC) nanocomposites. Three different blends formed by polystyrene (PS) homopolymer and PS-coated gold nanoparticles (PSSH@Au) were used as modifiers of asymmetric polystyrene-b-polymethylmethacrylate (PS-b-PMMA): PS26/PS26SH@Au, PS75/PS75SH@Au and PS167/PS167SH@Au (where the subscripts refer to the number of styrene monomeric units).The results indicated that all three blends used as modifiers (PSn/PSnSH@Au) were successfully located in the PS phase during thermally induced BC self-assembly for a composition range from 5 to 43 wt% without macro-phase separation. The PSnSH@Au moiety experienced molecular desorption, nanocrystal core coalescence and partial molecular re-encapsulation processes during thermal annealing, leading to sphere-like gold NPs with a larger average size (without exceeding an interdomain distance). Ligand chain length regulated the degree of coalescence and re-encapsulation, defining ultimate core size. Furthermore, proper combination of chain length and composition enabled tuning of NP partitioning and arrangement on different length scales through thermally activated cooperative assembly processes. These results have not only significant impact for establishing thermal processing as a useful tool for the precise control of NP size and distribution, but also much broader implications for many nanoparticle-based technologies.
热退火被用于自上而下地制造形态可控的金-嵌段共聚物（Au-BC）纳米复合材料。三种不同的共混物由聚苯乙烯（PS）均聚物和 PS 包覆的金纳米颗粒（PSSH@Au）组成，用作不对称聚苯乙烯-聚甲基丙烯酸甲酯（PS-b-PMMA）的改性剂：PS26/PS26SH@Au、PS75/PS75SH@Au 和 PS167/PS167SH@Au（下标指苯乙烯单体单元的数量）。结果表明，所有三种用作改性剂的共混物（PSn/PSnSH@Au）在热诱导 BC 自组装过程中都成功地位于 PS 相中，组成范围从 5 到 43wt%，没有发生宏观相分离。PSnSH@Au 部分在热退火过程中经历了分子解吸、纳米晶核团聚和部分分子再封装过程，导致具有更大平均尺寸的球形金 NPs（不超过畴间距离）。配体链长调节团聚和再封装的程度，从而定义最终的核心尺寸。此外，通过热激活协同组装过程，适当组合链长和组成可以调节 NP 在不同尺度上的分配和排列。这些结果不仅对建立热加工作为精确控制 NP 尺寸和分布的有用工具具有重要意义，而且对许多基于纳米粒子的技术也具有更广泛的意义。
