自组装PDMS基SERS基底的制备及性能研究

论文总字数：21666字

摘 要

表面增强拉曼散射是一种高灵敏度的分析方法，但是SERS基底的均匀性的差异会极大地影响测试结果。PDMS是目前最常用的制作微流控器件的材料，但是由于其强疏水性，在其上制作均匀、高增强性的SERS基底是一个难点。

本论文主要是采用静电吸附的方法，在PDMS基片上制备具有表面增强拉曼散射效应的银纳米颗粒。并研究该方法下制备条件（比如浸泡时间、浸泡浓度等）对基底形貌，表面增强拉曼散射活性及均匀性的影响，并寻找最佳实验条件达以到最佳表面增强拉曼效应的增强效果。实验变量主要有六类，分别是氧等离子机的处理、PDDA浸泡浓度、PDDA浸泡时间、离心银胶的转速、银胶浸泡时间以及银胶的浓度，采用控制变量法逐一探讨，分组对比得出最佳实验条件。最后通过电镜和分光光度计等手段研究附着在基片上银纳米颗粒的形貌，观察颗粒吸附在基底上的分布。通过对每组实验制作过程的观察和消光谱、SERS信号、电镜图片的分析，了解静电吸附法的作用机理。

实验最终得到以下结论：PDMS基片需要用氧等离子机进行预处理；PDDA浓度的最佳实验条件是15%；PDDA浸泡时间的最佳实验条件为6h；对于离心来说，2500转，40分钟是最适宜的，且离心后取沉降在离心管底部的颗粒；银胶浸泡时间的最佳实验条件为6h；银胶浓度的最佳实验条件为离心后稀释一倍，其浓度约为5.15*10^-6mol/L。

关键词：表面增强拉曼散射效应，静电吸附，银胶溶胶，控制变量

PREPARATION AND PROPERTIES OF SELF-ASSEMBLED

PDMS-BASED SERS SUBSTRATE

Abstract

Surface enhanced Raman scattering is a highly sensitive analytical method, but the uniformity of the SERS substrate will greatly affect the test results. PDMS is the most commonly used material for the production of microfluidic devices. However, it is difficult to make uniform and highly enhanced SERS substrate due to its strong hydrophobicity.

In this thesis, the silver nanoparticles with surface enhanced Raman scattering effect on PDMS substrate were prepared by electrostatic adsorption. That the effect of preparation conditions on the morphology(Such as soaking time, soaking concentration, etc.) and SERS activity and uniformity of the substrate was studied, and to find the optimum conditions to achieve the best SERS enhancement effect. There are six main experimental variables, namely, Treatment of oxygen plasma machine, PDDA soaking concentration, PDDA soaking time, the rotational speed of the centrifugal silver plastic, silver colloid soaking time and the concentration of silver colloid, The optimal experimental conditions are obtained by using the control variable method. Finally, the morphology of silver nanoparticles was studied by means of electron microscope and spectrophotometer, to study the distribution of particles adsorbed on the substrate. By observing the production process of each experiment and analysis of extinction spectrum, SERS signal and electron microscope image, understand the

mechanism of action of the electrostatic adsorption.

Finally, experimental obtained the following conclusions: PDMS substrate needs to be pretreated with oxygen plasma machine; The best experimental condition of PDDA concentration is 15%; The best experimental condition of PDDA soaking time is 6h; For centrifugation, the 2500 rpm, 40 minutes is the most appropriate, and after centrifugation, settling at the bottom of the centrifuge tube particles; The best experimental condition for the Silver colloid soaking time is 6h; The best experimental condition for the concentration of silver colloid was diluted after centrifugation, and its concentration was about

5.15*10-6mol/L.

KEY WORDS: Surface-enhanced Raman scattering effect, Electrostatic adsorption, Silver

colloid , Control variables

目 录

摘要 …………………………………………………………………………………2

Abstract …………………………………………………………………………… 3

1. 绪论 …………………………………………………………………………5

1.1 引言 ……………………………………………………………5

1.2 表面增强拉曼光谱 …………………………………………………5

1.2.1表面增强拉曼光谱的发现 ……………………………………5

1.2.2表面增强拉曼光谱的特点 ………………………………………6

1.2.3表面增强拉曼光谱的增强原理 …………………………………6

1.2.4 表面增强拉曼光谱的应用 …………………………………7

1.3微流控芯片 …………………………………………………8

1.3.1微流控芯片的进展 ………………………………………………8

1.3.2微流控芯片的的检测 ………………………………………9

1.4 本论文的主要工作安排 …………………………………………10

1. SERS基底的制备及性能研究 ……………………………………11

2.1 实验原理 ………………………………………………………11

2.2实验目的和意义 ……………………………………………………11

2.3实验材料 …………………………………………………………12

2.4方案设计 …………………………………………………………12

2.5实验方法和结果分析 …………………………………………13

1. 总结与分析 ……………………………………………………………21

3.1 结论分析 ……………………………………………………………21

3.2 总结展望 ……………………………………………………… 21

致谢 ………………………………………………………………………………22

参考文献（References） …………………………………………………………23

1. 绪 论

1.1 引言

印度科学家拉曼与其学生克里希南在一次实验中发现了拉曼散射。其现象可描述为：从分子上反射的光中，由于分子转动和振动的原因，反射光中会出现与入射光频率不同的光，这种光散射的现象称之为拉曼散射。分子与光子作用，散射光的频率不变，两者没有能量交换，称之为瑞利散射；分子与光子相互作用时有能量转移，散射光的频率与入射光不同，称之为拉曼散射。反之，如果光子的频率由于其接受了分子的振动能量和转动能量而升高，这种现象就叫做反斯托克斯散射^[1,2]。若光子的一部分能量转移给分子，使得光子的频率降低的现象称之为斯托克斯散射。

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