Truncated Wedge-Shaped Nanostructures Formed from Lateral Microphase Separation of Mixed Homopolymer Brushes Grafted on 67 nm Silica Nanoparticles: Evidence of the Effect of Substrate Curvature

详细信息    查看全文

• 作者：Jonathan M. Horton ; Saide Tang ; Chunhui Bao ; Ping Tang ; Feng Qiu ; Lei Zhu ; Bin Zhao
• 刊名：ACS Macro Letters
• 出版年：2012
• 出版时间：August 21, 2012
• 年：2012
• 卷：1
• 期：8
• 页码：1061-1065
• 全文大小：461K
• 年卷期：v.1,no.8(August 21, 2012)
• ISSN：2161-1653

文摘

Mixed poly(tert-butyl acrylate) (PtBA)/polystyrene (PS) brushes with controlled molecular weights and narrow polydispersities were synthesized from asymmetric difunctional initiator (Y-initiator)-functionalized 67 nm silica nanoparticles by sequential surface-initiated atom transfer radical polymerization of tBA at 75 掳C and nitroxide-mediated radical polymerization of styrene at 120 掳C in the presence of a free initiator in each polymerization. The Y-initiator-functionalized nanoparticles were prepared by the immobilization of a triethoxysilane-terminated Y-initiator onto the surface of 67 nm silica particles via an ammonia-catalyzed hydrolysis and condensation process. Transmission electron microscopy studies showed that mixed PtBA/PS brushes grafted on 67 nm silica nanoparticles with comparable molecular weights for the two polymers underwent lateral microphase separation after being cast from CHCl₃ and annealed with CHCl₃ vapor, producing distinct truncated wedge-shaped nanostructures. In contrast, under the same conditions, mixed PtBA/PS brushes grafted on 160 nm silica particles self-assembled into nanodomains with a more uniform width. This suggests that the truncated wedge-shaped nanostructures formed by mixed brushes on 67 nm silica nanoparticles originated from a higher substrate curvature.