分级微纳结构微球的可控制备及有序表面增强拉曼散射基底构筑

The technique of surface-enhanced Raman scattering (SERS) can provide important information of surface molecular structure and kinetic process directly. SERS-active substrates play the key role in SERS research. The conventional SERS substrates have the disadvantages of instability and poor reproducibility. So, the ordered SERS substrates obtained much more attention recently, due to their proerties of highly enhanced and reproducibility. During the past decade, increasing attention has been paid to nano/micro or hierarchically structured materials due to their unique physical and chemical properties. Although the in-situ growth on the templates surface is more an attractive approach to imitate the hierarachical structues, the relation between the micro/nano structure and the surface nature of templates is still confusion. In this work, hairy spheres are employed to construct micro/nano structrues.The hairy spheres are prepared by Atom Transfer Radical Polymerization (ATRP). By using the weak acid-base interaction (between hairy chains and the precusors), inorganic nanoparticles can nucleate and growth on the surface via in-situ sol-gel reaction. And we hope to verify the formation mechanism of berry-like polystyrene/silica in-situ sol-gel process and grasp the rules of building micro/nano structured composite spheres. Finally, we will facbircate ordered substrates via micro/nano hierarachically structured particles and develop an efficient, economic and controllable method for facbricating SERS-actived substrates with highly enhancement, reproducibility and reusable.

表面增强拉曼散射（SERS）是一种与纳米结构密切相关的光谱技术，在生物医药、材料及环境科学等领域具有广阔的应用前景。解决SERS 基底的稳定性、灵敏性和重复使用性，是其实现广泛应用的前提。本课题拟以"毛发状"聚合物微球为模板进行分级微纳结构微球的制备。通过控制模板表面毛发状聚合物链段的化学组成和聚集状态，探索在弱酸碱作用下，多层次微纳复合结构的演变规律，掌握此过程中驱动纳米粒子在模板表面成核、生长的关键要素，解决传统模板法负载纳米粒子时，微纳结构的可控性和重现性差等难题。利用毛发状微球的有序组装，结合原位反应，制备树莓状PS/SiO2/Ag/TiO2 微纳结构基底，提高SERS基底的稳定性、灵敏度和可重复使用性。项目完成有助于掌握微球表面毛发状链段在调控纳米粒子成核、生长过程中的关键问题，丰富模板法制备多微尺度复合微球的思路，为实现实用性有序SERS 基底的制备，提供理论指导和实验依据。

为解决传统聚合物模板法制备微纳结构复合微球重复性和结构可控性差的缺点，本项目开展了毛发状微球的制备、分级微纳结构有机/无机复合微球的制备以及SERS基底构筑及其性能研究。通过ATRP表面活性聚合和乳液聚合，制备出组成及结构可控的毛发状微球模板；通过原位溶胶凝胶反应制备有机无机复合微球。研究结果阐明了微球表面羧基与TEOS前驱体水解产物间的弱酸碱作用是控制二氧化硅纳米粒子在微球表面成核、生长的控制因素。微球表面含羧基可电离毛发链段能够实现果莓状或核壳状微球制备；表面含PEG非电离毛发链段阻碍二氧化硅纳米粒子的聚集；表面含有混合型毛发聚合物链段能够控制二氧化硅纳米粒子的尺寸和聚集形态。因此，通过控制微球表面聚合物毛发链段的组成、分子量及类型，实现了分级结构的可控制备。在此基础上，制备出结构多样化的聚苯乙烯/二氧化硅/银复合微球并用于SERS基底的构筑，结果表明该基底能够实现10-12M极低浓度罗丹明分子的检出。