Formation of polymeric nanoparticles viaBergman cyclization mediated intramolecular chain collapseElectronic supplementary information (ESI) available: Detailed experimental procedures for the synthesis and characterizations of monomers and copolymers, NMR spectra, DSC curves, AFM images, dielectric constant measurements, GPC curves. See DOI: 10.1039/c0jm03143g

Autor: Benchuan Zhu, Jianguo Ma, Zhiwen Li, Jing Hou, Xin Cheng, Guannan Qian, Pai Liu, Aiguo Hu
Zdroj: Journal of Materials Chemistry; Feb2011, Vol. 21 Issue 8, p2679-2683, 5p
Abstrakt: Polymeric nanoparticles were synthesized through Bergman cyclization mediated intramolecular chain collapse. Enediyne moieties were incorporated into linear polymers through copolymerization or post-polymerization modification. The resulted enediyne containing copolymers were then subjected to intramolecular chain collapse under ultra-dilute condition or applying a continuous addition technique. The occurrence of Bergman cyclization was confirmed with IR, NMR and DSC analysis. The intramolecular chain collapse was characterized with GPC, DSC, and AFM. Dramatic decreases of apparent molecular weights of linear copolymers were observed after Bergman cyclization. The structural diversity of enediyne precursors and mild chain collapse condition allow wide monomer selection, which facilitates preparation of a broad range of polymeric nanoparticles. Low-k dielectric thin films were prepared using polymeric nanoparticles through “porogen” approach. The packing tightness of polymeric nanoparticles showed strong influence on film formation behavior with MSSQ matrix. With tightly packed polymeric nanoparticles as sacrificial pore generators, thin films with dielectric constants of as low as 2.1 were obtained. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index