The Structure and Properties of Ultra-high density Polymer Brushes

超高密度聚合物刷的结构与性能

• 批准号: 12450385
• 负责人: FUKUDA Takeshi
• 金额: $ 10.82万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450385/
• 关键词: high-density polymer brush; swollen graft film; dry graft film; plate compressibility; non-scaling; glass transition temperature; surface properties; bulk properties; ポリマーブラシ; 超高密度ブラシ; 単分散ポリマーブラシ; リビングラジカル重合; 高伸長ブラシ; 高弾性ブラシ; AFM; フォースカーブ

Living radical polymerizations (LRPs) such as atom transfer radical polymerization (ATRP) and reversible addition-fragmentation transfer (RAFT) polymerization were applied to various solids (silicon wafer, polymer films, silica or metal nano-particles, etc.) with initiating sites chemically bound on their surfaces, establishing experimental techniques to prepare graft polymer films (polymer brushes) of differing monomers with controlled chain length and chemical structure and with a surface density as high as 0.7 chains/nm^2.These graft films were recognizable as a new molecular organization having characteristic properties, in both swollen and dry states, different from those of the equivalent cast films. For example, the polymer chains in the high-density film swollen by a good solvent are highly extended normally to the film surface, thus giving a film thickness of 80 to 90% of the fully stretched chain length. The plate compressibility of the swollen graft film disobeys the scaling theory, and that of the dry (melt) film is about 50% larger than the cast film. Moreover, the glass transition temperature T_g of the dry graft film is essentially different from that of the equivalent cast film in both low-molecular weight (film thickness < 50nm) and high-molecular weight regions. In particular, the experimental data indicate that the Tg of poly(methyl methacrylate) (PMMA) high-density graft films is about 8K higher than that of bulk PMMA even in the limit of high molecular weight, meaning that the high-density grafting has an effect not only to thin films but also to thick films and hence to the bulk of the films.

生命的自由基聚合（LRP），例如原子转移自由基聚合（ATRP）和可逆的添加裂变转移（RAFT）聚合，将聚合应用于各种固体（硅晶片，聚合物膜，硅或金属纳米粒子等），以化学作业将其构建膜，以建立构造技术，以建立构造技术，以建立实验，以建立实验（建立实验）（建立实验）（具有受控链长和化学结构的不同单体的刷子），表面密度高达0.7链/nm^2。这些移植膜在肿胀和干燥状态下具有特征性特性的新分子组织，与等效的铸造膜不同。例如，高密度膜中的聚合物链被良好的溶剂肿胀，正常延伸到膜表面，从而使膜的厚度为完全拉伸的链长的80％至90％。肿胀的移植膜的板压缩性不服从缩放理论，而干燥（熔体）膜的板块比铸造膜大约50％。此外，干移植膜的玻璃过渡温度T_G与低分子重量（膜厚度<50nm）和高分子重量区域中的等效铸造膜基本不同。特别是，实验数据表明，即使在高分子量的限制下，聚（PMMA）高密度移植膜的TG高约8K，即使在高分子量的极限上，这意味着高密度嫁接不仅具有薄膜的作用，而且对薄膜和薄膜的厚膜和膜的细胞也具有效果。