Self-condensing Atom Transfer Radical Polymerization from Surfaces: Nanocomposites of Multifunctional Hyperbranched Polymers

通过原子转移自由基聚合（ATRP）从二氧化硅（或金）纳米颗粒表面的自缩合乙烯基聚合（SCVP）导致在表面具有极高密度的官能团和精确的纳米尺度的混合纳米颗粒。为此目的，ATRP引发剂与二氧化硅颗粒共价连接，随后是在同一分子中具有丙烯酸单体和引发剂官能团的引发剂-单体（“引发剂对映体”）的SCVP。平均而言，超支化聚合物每个单体单元带有一个溴酯官能团。支化度和官能度可以通过与丙烯酸单体共聚来调节。溴酯官能团将通过化学转化或通过原子转移自由基加成进一步改性，以产生具有比线性接枝聚合物高几个数量级的表面密度的各种官能团。

Self-condensing vinyl polymerization (SCVP) via atom transfer radical polymerization (ATRP) from the surface of silica (or gold) nanoparticles leads to hybrid nanoparticles with an extremely high density of functional groups at the surface and precise nanoscopic dimensions. For this aim, ATRP initiators are covalently linked to silica particles, followed by SCVP of initiator-monomers ("inimers") having both an acrylic monomer and initiator function in the same molecule. On the average, the hyperbranched polymers carry one bromoester function per monomer unit. The degree of branching and functionality can be adjusted by copolymerization with acrylic monomers. The bromoester function will be further modified by chemical transformations or by atom transfer radical addition to result a variety of functional groups with surface densities which are by orders of magnitude higher than for linear grafted polymers.