摘 要

2004年，英国两位科学家Andre Geim和Konstantin Novoselov采用机械剥离定向热解石墨（Highly Oriented Pyrolytic Graphite）的措施获得了单层石墨烯。自从石墨烯问世以来，以其优异的特性，如：具有超高的载流子迁移率、优异的电学性能、与碳纳米管媲美的热导率、透光性以及优异的机械强度，引起了科学界和工业界极大的关注，被预测很可能会在诸多行业发生革命性的变化。目前，石墨烯在微电子器件、能量存储、生物材料、电极材料和复合材料等领域有着广泛的应用和极具潜力的前景。

由于石墨烯超高的稳定性以及层与层之间强有力的范德华力，很容易发生团聚。为了提高石墨烯的分散性及可利用性，我们以氧化石墨烯为原料，采用NaBH₄为还原剂将氧化石墨烯及Ag 还原进行覆银改性，在石墨烯表面附着纳米银，扩大层间距，减弱范德华力；然后考察覆银石墨烯在不同类型表面活性剂体系中的分散性，制备覆银石墨烯分散液，并对此分散液进行性能检测，考察其是否能改善黑孔液黑孔化性能。本文主要工作如下：

（1）氧化石墨烯(GO)的表征。经过对氧化石墨烯（GO）进行一系列表征，如：紫外分析、红外分析、热重分析以及厂家提供的AFM分析及SEM分析等，证实了氧化石墨烯表面含有-OH、-COOH、-O-等丰富的含氧基团，共轭结构不明显；且通过热重分析得知，氧化石墨烯的热稳定性较差；通过AFM分析、XRD分析以及SEM分析，氧化石墨烯的片层大小为0.5-5um,片层厚度0.6-1.0nm，层间距为0.817nm，且表面光滑、平整，未出现明显的褶皱，证明氧化石墨烯的层数很少，性能优异。

（2）覆银石墨烯(Ag-G)的制备与表征。采用NaBH₄将氧化石墨烯和Ag 还原制备覆银石墨烯，并对覆银石墨烯进行一系列分析。分析结果表明：经还原后，覆银石墨烯表面-COOH、-O-等含氧基团已被基本除去，而-OH无明显变化；经过覆银过后的石墨烯热稳定性增强；相对于石墨烯而言，覆银石墨烯层间距夸大，减弱了范德华力；紫外分析表明纳米尺度的银附着在石墨烯表面，制备得到我们目标物覆银石墨烯。

（3）覆银石墨烯(Ag-G)水系分散液的制备。通过考察表面活性剂种类、浓度、分子量和复配对覆银石墨烯分散性能的影响，通过吸光度及ζ电位的测量，表明阴离子与非离子表面活性剂对其分散效果较好，且硅烷偶联剂KH-550对其分散有明显效果，分散液浓度达到0.89mg/ml。对覆银石墨烯分散液进行固含量、电导率、ζ电位和接触角分析，考察其分散稳定性及代替市场常用黑孔液的可能性。

关键词：石墨烯；纳米银改性；表面活性剂；分散

Abstract

Two scientists at the University of Manchester, Andre Geim and Konstantin Novoselov, obtained monolayer graphene by mechanically exfoliating oriented pyrolytic graphite. Since the advent of graphene, due to its excellent properties, such as: with high carrier mobility, high conductivity, and the high thermal conductivity comparable to carbon nanotubes, light transmission and excellent mechanical strength, graphene got great interest by The scientific community and industry, which is predicted to produce revolutionary changes in many areas. At present, graphene has a wide range of applications and great potential prospects in nano-electronic devices, energy storage, biological materials, electrode materials and composite materials and other fields.

Due to the high stability of graphene and the strong van der Waals force between layers, it is easy to reunite. In order to improve the dispersibility and availability of graphene, we reduced graphene oxide and Ag with NaBH₄ as the reducing agent, and the nano-silver was attached to the surface of graphene. Therefore, the van der Waals force was weakened. The dispersibility of modified graphene in different types of surfactant system was investigated, and the aqueous dispersion of graphene coated silver was prepared and the performance of the dispersion was investigated. It was investigated whether it could improve the black hole performance. The main work of this paper is as follows:

(1) Characterization of graphene oxide(GO). Through a series of characterization of the graphene, such as UV analysis, infrared analysis, thermogravimetric analysis and AFM analysis and SEM analysis provided by the manufacturer, it is confirmed that the surface of the graphene oxide contains -OH, -COOH and -O- The results show that the thermal stability of the graphene oxide is poor. By means of AFM analysis, XRD analysis and SEM analysis, the size of the graphene oxide is 0.5- 5um, the thickness of the lamellae is 0.6-1.0nm, the interlayer spacing is 0.817nm, and the surface is smooth, and no obvious folds are observed. It is proved that the graphene oxide has few layers and excellent performance.

(2) Preparation and characterization of silver-coated graphene(Ag-G). The silver-coated graphene was prepared by reducing graphene and Ag with NaBH₄, and a series of analysis of Ag-G was carried out. The results show that the oxygen-containing groups such as -COOH and -O- have been removed, and the -OH has no obvious change after the reduction. The thermal stability of the silver-coated graphene is enhanced. Compared to graphene, the layer spacing of silver-coated graphene is exaggerated and the van der Waals force is weakened. The UV analysis and TEM analysis show that the nanometer scale silver is attached to the surface of the graphene to prepare our target silver-coated graphene.

(3) Preparation of silver-coated graphene aqueous dispersion. The effects of surfactants, concentration, molecular weight and complexing on the dispersibility of silver-coated graphene were investigated. The results showed that the dispersions of the anions and nonionic surfactants were better, and the silane coupling agent KH-550 has a significant effect on its dispersion. The dispersion stability and the possibility of replacing the black hole in the market were investigated by analyzing the solid content, conductivity, zeta potential of the silver-coated graphene dispersion.

Key words: graphene; nano-silver modification; surfactant; aqueous dispersion

目 录

摘 要 1

Abstract 2

目 录 4

第一章 绪论 6

1.1 石墨烯简介 6

1.1.1 石墨烯结构与性质 6

1.1.2 石墨烯制备方法 9

1.1.3 石墨烯的应用 12

1.2 石墨烯改性现状 14

1.2.1 共价键改性 15

1.2.2 非共价键改性 18

1.2.3 掺杂改性 19

1.2.4 复合改性 19

1.3 石墨烯水系分散液研究 20

1.3.1 石墨烯分散液研究进展 20

1.3.2 石墨烯分散液应用前景 20

1.3.3 黑孔液简介 21

1.4 本课题研究目的、意义、内容与创新点 22

1.4.1 目的与意义 22

1.4.2 研究内容 22

1.4.3 研究的创新点 22

第二章 氧化石墨烯（GO）结构与性能表征 23

2.1 引言 24

2.2 氧化石墨烯（GO）的分析与表征 24

2.3 结果与讨论 24

2.3.1 氧化石墨烯紫外图谱分析 24

2.3.2 氧化石墨烯红外图谱分析 25

2.3.3 氧化石墨烯热重分析 25

2.3.4 氧化石墨烯拉曼分析 26

2.3.5 氧化石墨烯XRD分析 27

2.3.6 氧化石墨烯AFM分析 27

2.3.7 氧化石墨烯SEM分析 28

2.4 本章小结 28

第三章 覆银石墨烯（Ag-G）的制备与表征 29

3.1 引言 29

3.2 实验部分 29

3.2.1 实验药品与仪器 29

3.2.2 实验步骤与原理 30

3.2.3 测试与表征 31

3.3 结果与讨论 31

3.3.1 覆银石墨烯紫外光谱分析 31

3.3.2 覆银石墨烯红外光谱分析 32

3.3.3 覆银石墨烯热重分析 33

3.4 本章小结 33

第四章 覆银石墨烯（Ag-G）水系分散液的制备与性能检测 34

4.1 引言 34

4.2 实验部分 34

4.2.1 实验药品与仪器 34

4.2.2 实验步骤 35

4.3 覆银石墨烯分散液分散性结果与讨论 37

4.3.1 不同pH对Ag-G分散性影响 37

4.3.2 不同超声时间对Ag-G分散性影响 38

4.3.3 不同表面活性剂对Ag-G分散性影响 39

4.3.4 表面活性剂分子量对Ag-G分散性影响 41

4.3.5 表面活性剂复配对Ag-G分散性影响 42