铝纳米粒子表面引发聚合制备核壳纳米结构

利用硅烷偶联剂引发法制备核壳结构金属铝纳米粒子(Al NPs)@聚合物, 并研究了聚合反应时间和单体浓度对核壳结构尺寸的影响. 首先合成了硅烷偶联引发剂{2-溴-2-甲基-3-(三甲氧基硅基)丙基]丙酰胺}, 并通过在甲苯中回流的方法, 将其锚定在金属铝纳米粒子表面. 然后, 在粒子表面引发甲基丙烯酸甲酯的原子转移自由基聚合, 形成聚甲基丙烯酸甲酯(PMMA)壳层. 通过核磁共振波谱仪(NMR)和傅里叶变换红外光谱仪 (FTIR)证明了引发剂和PMMA的成功接枝. 透射电子显微镜(TEM)图像表明, PMMA改性后的金属铝纳米粒子的尺寸和形貌基本不变, 且被厚度约为15 nm聚合物壳层完整均匀地包覆. 此外, 利用动态光散射(DLS)进一步揭示了聚合时间和单体浓度对核壳结构水合直径(D_h)的影响, 发现延长聚合时间或增加单体浓度均可显著提高核壳结构尺寸.

Synthesis of Aluminum Nanoparticles@Polymer Core-shell Nanostructures by Surface-initiated Polymerization

Core-shell structured aluminum nanoparticles（Al NPs） grafted with poly（methyl methacrylate）（PMMA） were successfully prepared by the surface-initiated atom transfer radical polymerization of methyl methacrylate（MMA）. The Al NPs were modified by the surface initiator which was synthesized by the condensation reaction between （3-aminopropyl） trimethoxysilane and α-bromoisobutyryl bromide. The initiator was bonded to the Al NPs surface by the reaction of hydrolysable group of the organosilane with hydroxyl of alumina and initiated the atom transfer radical polymerization of MMA. Fourier transform infrared spectroscopy（FTIR） and ¹H nuclear magnetic resonance（¹H NMR） spectra confirmed the successfully grafting of initiator and PMMA on the surface of Al NPs. Transmission electron microscopy（TEM） images showed that Al NPs were completely coated by a uniform polymer shell with a thickness of about 15 nm. Moreover， dynamic light scattering（DLS） was used to further reveal the effect of polymerization time and the monomer concentration on the hydrodynamic diameter（D_h） of Al NP@PMMA core-shell structures. The D_hof Al NP@PMMA can be remarkably elevated by the extension of polymerization time or increase of monomer concentration.