Synthesis of Poly(vinylacetylene) Block Copolymers by Atom Transfer Radical Polymerization
Synthesis of Poly(vinylacetylene) Block Copolymers by Atom Transfer Radical Polymerization
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DOI：
10.1021/ma8022074
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发表时间：
2008-11
期刊：
影响因子：
5.5
通讯作者：
J. Aimi;L. Mccullough;K. Matyjaszewski
中科院分区：
文献类型：
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作者：
J. Aimi;L. Mccullough;K. Matyjaszewski
有序纳米结构碳材料的制备由于其在许多应用中的潜力而引起了人们的兴趣，这些应用包括能量存储设备、1传感器、2和电子设备。3最近，一种新的低成本路线，以制备定义明确的纳米碳材料的基础上裂解的嵌段共聚物，包含碳前体嵌段，如聚丙烯腈（PAN）和牺牲嵌段（如，聚（丙烯酸正丁酯）。4-8所得的碳结构依赖于嵌段共聚物的自组织以形成良好有序的形态，9以及可以通过定义每个嵌段的相对组成在纳米级中控制的制造条件。然而，来自PAN前体的碳也含有高达7%的氮，这导致影响材料电子特性的缺陷位点。这一事实使我们探索其他类型的嵌段共聚物，可以导致在纯碳结构的制备。聚（乙烯基乙炔）（PVA），一种聚合物，结构类似于PAN没有固有的氮基团，可能具有潜力，得到类似的纳米结构的材料，具有高的碳产率，而不存在预先形成的n型掺杂剂。已经有一些关于通过阳离子聚合、10阴离子聚合、11-14热聚合、13或常规自由基聚合从简单共轭烯炔分子制备PVA的报道。15-17包括VA的2-甲基衍生物的VA衍生物的阴离子聚合表现出类似活性的特征。18，19在150-400 ℃的温度范围内对PVA进行热处理导致形成具有中等导电性和热稳定性的共轭交联材料。然而，乙烯基乙炔的受控聚合仍然具有挑战性，这是由于其共轭特性和与侧链乙炔基团和酸性乙炔质子的存在相关的副反应。乙烯基乙炔聚合的困难限制了含PVA材料作为纳米结构碳体系的有效高产率碳前体的研究。
The preparation of well-ordered nanostructured carbon materials has attracted interest due to their potential in a number of applications including energy storage devices, 1 sensors, 2 and electronics devices. 3 Recently, a novel lowcost route to prepare well-defined nanocarbon materials was developed based on the pyrolysis of block copolymers that contains a carbon precursor block such as polyacrylonitrile (PAN) and a sacrificial block (eg, poly (n-butyl acrylate). 4-8 The resulting carbon structures rely on the self-organization of block copolymers to form well-ordered morphologies, 9 and fabrication conditions which can be controlled in the nanoscale by defining the relative compositions of each block. Carbons derived from PAN precursors, however, also contain up to 7% nitrogen, which results in defect sites that affect the electronic properties of the materials. This fact led us to explore other types of block copolymers that could result in the preparation of pure carbon structures.Poly (vinylacetylene)(PVA), a polymer that structurally resembles PAN without the inherent nitrogen group, may possess the potential to give similar nanostructured materials with high carbon yield without the presence of preformed n-type dopants. There have been a few reports on the preparation of PVA from simple conjugated enyne molecules by cationic polymerization, 10 anionic polymerization, 11-14 thermal polymerization, 13 or conventional free radical polymerization. 15-17 The anionic polymerization of VA derivatives including 2-methyl derivatives of VA exhibit a living-like character. 18, 19 Thermal treatment of PVA in the temperature range of 150-400 C resulted in the formation of conjugated cross-linked materials with moderate electrical conductivity and thermal stability. 10 However, controlled polymerization of vinylacetylene remains challenging due to its conjugated character and side reactions related to the presence of pendant acetylene group and the acidic acetylene proton. The difficulty in polymerizing vinylacetylene has limited the investigation of PVA-containing materials as effective high yield carbon precursors for nanostructured carbon systems.