摘要
本文采用三(2-苯基吡啶)合铱(Ir(ppy)_3)催化体系,通过激光催化可控自由基聚合的方法在硅片表面获得图案化的PEG聚合物刷,并采用椭圆偏光仪、X射线光电子能谱(XPS)和光学显微镜等方法表征了所得聚合物刷的厚度、表面化学组成和图案结构;探讨了Ir(ppy)_3催化体系下激光调控表面自由基聚合过程,提出自由基"迁移"终止动力学模型。实验数据的模型拟合研究表明自由基"迁移"终止模型较好地描述了PEG聚合物刷生长过程(R^2>0.946):在聚合初始阶段提高催化剂浓度、光照强度、单体浓度和接枝密度均可提高聚合物刷的生长速率;随光照时间的增加,自由基"迁移"终止效应会抑制聚合物刷厚度的持续增长,提高光照强度和单体浓度会降低自由基"迁移"终止效应,而提高催化剂浓度和接枝密度会提升自由基"迁移"终止效应。
Preparation of poly（ethylene glycol）（PEG） brush on a substrate surface is of great significance for the development of biomedical research and interface science. With the system of fac-Tris（2-phenylpyridine） iridium（III）（Ir（ppy）3） photocatalyst, patterned PEG brushes were prepared on a silicon surface via laser-mediation controlled radical polymerization. Ellipsometry, X-ray photoelectron spectroscopy（XPS） and optical microscope were applied to characterize the brush thickness, chemical composition and micro-patterns, respectively. With the discussion of polymerization process under Ir（ppy）3 photocatalysis, a kinetic model based on radical ＂migrate＂ termination process was proposed. The experimental data fitting results prove the feasibility of proposed ＂termination＂ model to depict the polymerization process（R20.946）. At the starting stage of polymerization, increasing catalyst concentration, light intensity, monomer concentration and initiator grafting density would promote the brush growth rate. With illumination time going, the radical ＂migrate＂ termination would hinder the continuous brush thickness growth; higher light intensity or higher monomer concentration would suppress the radical ＂migrate＂ termination, while higher catalyst concentration or higher initiator grafting density would promote the radical ＂migrate＂ termination.
作者
刘嵩
马玉录
赵海利
马康
沙金
谢林生
LIU Song;MA Yulu;ZHAO Haili;MA Kang;SHA Jin;XIE Linsheng(Engineering Center of Efficient Green Process Equipment and Energy Conservation of Ministry of Education,East China University of Science and Technology,Shanghai 200237,China)
出处
《材料科学与工程学报》
CAS
CSCD
北大核心
2018年第5期752-758,共7页
Journal of Materials Science and Engineering
基金
国家自然科学青年基金资助项目(51503065)
博士后基金资助项目(2015M571505)
关键词
光催化
可控自由基聚合
聚合物刷
动力学
photocatalyst
controlled radical polymerization
polymer brushes
kinetics
