Silica-diblock fluoropolymer hybrids synthesized by surface-initiated atom transfer radical polymerization
作者:Hongpu Huang、Ling He
DOI:10.1039/c3ra47393g
日期:——
Silica/diblock fluoropolymer hybrids SiO2-g-PMMA-b-P12FMA for coatings were synthesized by the silica surface-initiating atom transfer radical polymerization (SI-ATRP) of methylmethacrylate (MMA) and dodecafluoroheptyl methacrylate (12FMA). Silica surface initiator (SiO2-initiator) was obtained by 10–25 nm fumed silica particles grafted hydrosilylated undec-10-enyl, 2-bromo-2-methyl propionate with a density of 0.573 mmol g−1. The SI-ATRP approach in this paper displays the diagnostic criteria of controlled radical polymerization by the analysis of 1H NMR, 19F NMR and SEC-MALLS analysis, after comparing with the conventional initiator of ethyl 2-bromoisobutyrate (EBiB) for the E-PMMA-b-P12FMA diblock copolymer. Three mass ratios of SiO2-initiator/MMA/12FMA as 1/72.50/18.15, 1/72.50/45.38 and 1/181.26/18.15 were used to obtain the SiO2-g-PMMA-b-12FMA hybrids. The hybrids show 25–30 nm core–shell particles in CHCl3 solution composed of a P12FMA core and PMMA shell, but densely twined together as agglomerated particles. The PMMA-b-P12FMA shell grafted onto silica particles obviously increases the surface roughness of the film (50–500 nm), more than the E-PMMA-b-12FMA film (30 nm), and thereby contributes to the hydrophobic (112–118°) and oleophobic (45–78°) properties of the films. Increasing the P12FMA concentration (1/72.50/45.38) could result in stronger migration of the P12FMA segments onto the film surface, and therefore led to a lower surface free energy (10.97 mN m−1), increased advancing and receding for water contact angles (112° and 108°) and the highest cetane contact angles (74° and 70°), the lower water absorption and viscoelasticity, but a high thermostability at 420–450 °C.
通过甲基丙烯酸甲酯(MMA)和甲基丙烯酸十二氟庚酯(12FMA)的二氧化硅表面引发原子转移自由基聚合(SI-ATP)合成了用于涂料的二氧化硅/嵌段含氟聚合物杂化物 SiO2-g-PMMA-b-P12FMA。二氧化硅表面引发剂(SiO2-initiator)由 10-25 nm 气相二氧化硅颗粒接枝水硅烷化的十一-十烯基、2-溴-2-甲基丙酸酯获得,密度为 0.573 mmol g-1。本文中的 SI-ATRP 方法与 E-PMMA-b-P12FMA 二嵌段共聚物的传统引发剂 2-溴异丁酸乙酯 (EBiB) 相比,通过 1H NMR、19F NMR 和 SEC-MALLS 分析,显示了受控自由基聚合的诊断标准。SiO2 引发剂/MMA/12FMA 的三种质量比分别为 1/72.50/18.15、1/72.50/45.38 和 1/181.26/18.15,从而得到 SiO2-g-PMMA-b-12FMA 混合物。混合物在 CHCl3 溶液中显示出 25-30 nm 的核壳颗粒,由 P12FMA 核和 PMMA 壳组成,但密集缠绕在一起成为团聚颗粒。与 E-PMMA-b-12FMA 薄膜(30 nm)相比,接枝到二氧化硅颗粒上的 PMMA-b-P12FMA 外壳明显增加了薄膜的表面粗糙度(50-500 nm),从而增强了薄膜的疏水(112-118°)和疏油(45-78°)特性。增加 P12FMA 的浓度(1/72.50/45.38)可使 P12FMA 片段更强地迁移到薄膜表面,从而降低表面自由能(10.97 mN m-1),增加水接触角(112° 和 108°)和最高十六烷接触角(74° 和 70°)的前进和后退,降低吸水性和粘弹性,但在 420-450 °C 下具有较高的热稳定性。