通过“接枝到”方法合成两种聚（甲基丙烯酸甲酯-b-3-（三甲氧基硅基）丙基甲基丙烯酸酯）/SiO₂ 杂化材料并进行比较

Synthesis and comparison of two poly (methyl methacrylate-b-3-(trimethoxysilyl)propyl methacrylate)/SiO2 hybrids by "grafting-to" approach.

作者信息

Huang Hongpu, He Ling, Huang Kehan, Gao Min

机构信息

Department of Chemistry, School of Science, Xi'an Jiaotong University, Xi'an 710049, China.

出版信息

J Colloid Interface Sci. 2014 Nov 1;433:133-140. doi: 10.1016/j.jcis.2014.07.027. Epub 2014 Jul 30.

DOI:10.1016/j.jcis.2014.07.027

PMID:25127293

Abstract

Two copolymer/SiO2 hybrids are prepared by growing SiO2 on the template of well -structured diblock copolymer PMMA-b-PMPS using a "grafting-to" approach. PMMA-b-PMPS is obtained by atom transfer radical polymerization (ATRP) of methyl methacrylate (PMMA) and 3-(trimethoxysilyl)propyl methacrylate (PMPS) using a brominated initiator end group termed 1H,1H,2H,2H-heptadecafluoro (F-Br) and a conventional initiator of ethyl 2-bromoisobutyrate (EBiB), respectively. The "grafting-to" approach is controlled at HCl for 24h by hydrolysis and condensation of Si(OCH3)3 groups in PMPS with tetraethyl orthosilicate (TEOS) to gain both hybrids of F-PMMA-b-PMPS/SiO2 (by F-Br initiator) and E-PMMA-b-PMPS/SiO2 (by EBIB initiator). Comparatively, a little amount of fluorine content provided by F-Br is able to tighten the size of self-assembled micelles, to improve wettability and the viscoelasticity of F-PMMA-b-PMPS film due to F-Br migrating onto the film surface. Therefore, the surface of F-PMMA-b-PMPS film is sufficiently hydrophobic (99° and Δf=2941Hz) than E-PMMA-b-PMPS film (94°and Δf=4820Hz), and the viscoelasticity of the adsorbed layer for F-PMMA-b-PMPS (ΔD/Δf=-0.112) film is much harder than E-PMMA-b-PMPS/SiO2 (ΔD/Δf=-0.071). On the other hand, the cross-linked silica in PMMA-b-PMPS/SiO2 could also increase water contact angels of films (100-107°) and decrease the water absorption (Δf=704-798Hz). The influence on the viscoelasticity of the adsorbed layer by the fluorine group is much more obvious than the cross-linked silica, therefore F-PMMA-b-PMPS/SiO2 (ΔD/Δf=-0.347) and F-PMMA-b-PMPS (ΔD/Δf=-0.112) films have harder adsorbed layer than E-PMMA-b-PMPS/SiO2 (-0.071) and F-PMMA-b-PMPS films (-0.042). However, compared with a slightly improvement in thermo stability by F-Br, the cross-linked silica in PMMA-b-PMPS/SiO2 performs significantly improving thermal decomposition temperature at 300°C and 350°C.

摘要

通过“接枝到”方法，在结构规整的二嵌段共聚物聚甲基丙烯酸甲酯 -b-聚甲基丙烯酸3-(三甲氧基硅基)丙酯（PMMA-b-PMPS）模板上生长二氧化硅，制备了两种共聚物/二氧化硅杂化材料。聚甲基丙烯酸甲酯 -b-聚甲基丙烯酸3-(三甲氧基硅基)丙酯是分别使用端基为溴化的1H,1H,2H,2H-十七氟（F-Br）的引发剂和传统的2-溴异丁酸乙酯（EBiB）引发剂，通过甲基丙烯酸甲酯（PMMA）和甲基丙烯酸3-(三甲氧基硅基)丙酯（PMPS）的原子转移自由基聚合（ATRP）得到的。“接枝到”方法通过在盐酸中用正硅酸乙酯（TEOS）使PMPS中的Si(OCH₃)₃基团水解和缩合24小时来控制，以得到F-PMMA-b-PMPS/SiO₂（通过F-Br引发剂）和E-PMMA-b-PMPS/SiO₂（通过EBIB引发剂）两种杂化材料。相比之下，F-Br提供的少量氟含量能够收紧自组装胶束的尺寸，由于F-Br迁移到薄膜表面，从而提高F-PMMA-b-PMPS薄膜的润湿性和粘弹性。因此，F-PMMA-b-PMPS薄膜的表面比E-PMMA-b-PMPS薄膜（94°和Δf = 4820Hz）具有足够的疏水性（99°和Δf = 2941Hz），并且F-PMMA-b-PMPS（ΔD/Δf = -0.112）薄膜吸附层的粘弹性比E-PMMA-b-PMPS/SiO₂（ΔD/Δf = -0.071）硬得多。另一方面，PMMA-b-PMPS/SiO₂中的交联二氧化硅也可以增加薄膜的水接触角（100 - 107°）并降低吸水率（Δf = 704 - 798Hz）。氟基团对吸附层粘弹性的影响比交联二氧化硅更明显，因此F-PMMA-b-PMPS/SiO₂（ΔD/Δf = -0.347）和F-PMMA-b-PMPS（ΔD/Δf = -0.112）薄膜的吸附层比E-PMMA-b-PMPS/SiO₂（-0.071）和F-PMMA-b-PMPS薄膜（-0.042）更硬。然而，与F-Br对热稳定性的轻微改善相比，PMMA-b-PMPS/SiO₂中的交联二氧化硅在300°C和350°C时能显著提高热分解温度。