Self-Assembly of Heteroarms Core-Shell Polymeric Nanoparticles (HCPNs) and Templated Synthesis of Gold Nanoparticles within HCPNs and the Superparticles
Self-Assembly of Heteroarms Core-Shell Polymeric Nanoparticles (HCPNs) and Templated Synthesis of Gold Nanoparticles within HCPNs and the Superparticles
复制标题
异臂核壳聚合物纳米粒子 (HCPN) 的自组装以及 HCPN 和超粒子内金纳米粒子的模板合成
DOI：
10.1021/ma9009643
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发表时间：
2009-09-22
期刊：
影响因子：
5.5
通讯作者：
Jiang, Ming
中科院分区：
文献类型：
--
作者：
Cheng, Fei;Zhang, Kaka;Jiang, Ming
本文报道了杂臂核壳聚合物纳米粒子（HCPNs）自组装成球形超粒子，以及在HCPNs和超粒子中合成金纳米粒子。采用两步阴离子聚合法合成了以聚苯乙烯（PS）/聚4-乙烯基吡啶（P4 VP）为杂臂、交联网络聚（4VP-co-二乙烯基苯）为核的HCPNs。在第一步中，通过在THF中使用正丁基锂引发苯乙烯来制备活性PS链。在第二步中，4VP和DVB的共聚由活性PS链引发。由此制备的HCPNs在结构上具有两个特征。(1)HCPN是大的（HCPN在DMF中的平均流体动力学半径< R-h >为111 nm，而< R-h >所报道的杂臂星星聚合物的平均流体动力学半径小于10 nm），并且当它们分散在溶剂如DNF和酸性水中时是柔性的。(2)PS臂设计为比P4 VP臂长得多。这两个特征导致HCPNs在普通溶剂和杂臂选择性溶剂中的有趣行为。在常用溶剂DMF中，HCPNs发生溶胀，λ < R-h >= 111 nm.在甲苯中，PS的选择性溶剂，较长的PS臂屏蔽短的不溶性P4 VP链，使HCPNs单独分散与< R-h >80 nm的α;短的P4 VP臂崩溃，和核心收缩。在酸性水中，这是一个选择性溶剂较短的P4 VP臂，HCPNs自组装成大的球形超粒子，平均< R-h >为187 nm。上述两个结构特征被认为是这种大的和各向同性的HCPNs的规则自组装所必需的。此外，无论是在甲苯中的HCPNs和在酸性水溶液中的超微粒子被用作模板，制备金纳米粒子（Au NPs）。当使用甲苯中的HCPNs作为模板时，具有约100 μ m的尺寸的Au NPs被制备出来。2-7纳米分散在交联核的外围，形成树莓状形态。当超微粒子作为模板时，AuNP/超微粒子复合纳米粒子的形貌依赖于溶剂的组成。在0.1 M HCl水溶液中，Au NPs位于超微粒的外围，形成厚度约为100 nm的金壳。50 nm。然而，在0.1 M HCl水溶液/DMF混合溶剂（9：1，v/v）中，HAuCl 4前体可以渗透到超粒子内的P4 VP结构域中，还原后在模板内形成树枝状的Au NP团簇。
Here we report the self-assembly of heteroarm core-shell polymeric nanoparticles (HCPNs) into spherical superparticles and Synthesis of gold nanoparticles within the HCPNs and the superparticles. HCPNs with polystyrene (PS)/poly(4-vinylpyridine) (P4VP) as the heteroarms and the cross-linked network poly(4VP-co-divinylbenzene) as the core were synthesized via a two-step anionic polymerization method. In the first step, living PS chains were prepared by initiating styrene using n-butyllithium in THF. In the second step, copolymerization of 4VP and DVB was initiated by the living PS chains. The HCPNs thus prepared have two features in the structure. (1) The HCPNs are large (the average hydrodynamic radius < R-h > of the HCPNs in DMF is 111 nm, whereas < R-h > of reported heteroarms star polymers are less than 10 nm) and flexible when they are dispersed in the solvents such as DNF and acidic water. (2) The PS arms are designed to be considerably longer than the P4VP arms. These two features led to interesting behaviors of the HCPNs in both the common solvent and the selective solvents for the heteroarms. In DMF, the common solvent, the HCPNs were swollen and with a < R-h > of 111 nm. In toluene, the selective solvent for PS, the longer PS arms shielded the short insoluble P4VP chains so that the HCPNs were individually dispersed with a < R-h > of 80 nm; the short P4VP arms collapsed, and the core shrank. In acidic water, which is a selective solvent for the shorter P4VP arms, the HCPNs self-assembled into large spherical superparticles with an average < R-h > of 187 nm. The above-mentioned two structural features are thought necessary for the regular self-assembly of such large and isotropic HCPNs. Furthermore, both HCPNs in toluene and the superparticles in acidic aqueous solution were used as templates to prepare gold nanoparticles (Au NPs). When HCPNs in toluene were used as the template, the Au NPs with a size of ca. 2-7 nm were scattered at the periphery of the cross-linked cores, forming raspberry-like morphology. When the superparticles were used as the template, the morphology of AuNP/superparticle composite nanoparticles depended on the solvent composition. In 0.1 M aqueous HCl solution, Au NPs were located at the periphery of the superparticles, forming gold shells with a thickness of ca. 50 nm. However, in 0.1 M HCl aqueous solution/DMF mixed solvent (9:1, v/v), the HAuCl4 precursor could penetrate into the P4VP domains within the superparticles, forming dendron-like Au NP clusters within the template after the reduction.