摘 要

随着化石能源的短缺以及环境污染的加重，人们迫切寻找一种新型的可再生清洁能源，此时太阳能凭借其普遍、无害、巨大、长久进入人们的视线，而太阳光中的近红外光更容易被人利用，光能更容易转换成热能。因此，研究近红外光光热转换材料具有重要价值。如何使得光热转换材料的转换效率增大是目前影响光热转化材料发展和大规模应用的关键问题，石墨烯作为一种制造成本、光吸收效率高的低碳基材料备受人们青睐，成为多个学科领域的研究者们竞相研究的热点。

作为一种优良的光热转化材料，石墨烯/聚合物基纳米复合材料广泛应用于医学，凭借其优秀的光热转换性能，成功开辟了癌症治疗的新道路。由于石墨烯对近红外光的强吸收特性以及其高的光热转化效率使其在光热远程智能控制领域崭露头角，由石墨烯/聚合物基纳米复合材料构建的光热驱动控制系统避免了传统驱动器复杂外部组件的影响，具有局部、无线、远程驱动控制的优势，成为国内外电子、新材料、新能源、航空航天、生物医疗等领域研究的热点。前人的实验研究表明，石墨烯/聚合物基纳米复合材料的力学性能与填充相石墨烯的浓度、形态等以及温度等因素有关，但未有针对石墨烯尺寸、填充浓度、辐照光强、时间等因素对光热转化的影响机制鲜见开展，使得实现光热转化的精确控制缺乏依据。本文基于Maxwell-Garnett有效介质理论（MG理论）分析高频率近红外光照射下复合材料的等效电导率，进而推导出材料的有效介电常数，与能量平衡方程和牛顿冷却定律相结合构建理论模型，尝试揭示石墨烯尺寸、填充浓度、辐照光强、时间以及辐照频率等因素对光热转化性能的影响。

关键词：石墨烯/聚合物基纳米复合材料；有效介质理论；近红外光；光热效应；光热转化

Abstract

With the shortage of fossil energy and the aggravation of environmental pollution, people are eagerly looking for a new type of renewable and clean energy. At this time, solar energy enters people's sight with its universal, harmless, huge, and long-term, and the near infrared light in the sun is easier to be used by people, and light energy is easier to convert into heat energy. Therefore, it is of great value to study near-infrared light-to-heat conversion materials. How to increase the conversion efficiency of light-to-heat conversion materials is currently a key issue affecting the development and large-scale application of light-to-heat conversion materials. As a low-carbon-based material with high manufacturing cost and high light absorption efficiency, graphene is favored by people and has become Researchers in multiple subject areas are competing for research hotspots.

As an excellent light-to-heat conversion material, graphene/polymer-based nanocomposites are widely used in medicine. With its excellent light-to-heat conversion performance, it has successfully opened up a new path for cancer treatment. Due to the strong absorption characteristics of graphene to near-infrared light and its high light-to-heat conversion efficiency, it has emerged in the field of remote intelligent control of light and heat. The influence of the complex external components of the driver has the advantages of local, wireless and remote drive control, and has become a hot spot in the field of electronics, new materials, new energy, aerospace, biomedicine and other fields at home and abroad. Previous experimental studies have shown that the mechanical properties of graphene/polymer-based nanocomposites are related to the graphene concentration, morphology, and temperature of the nanocomposites, but no research institute has studied the influence mechanism of graphene size, filling concentration, radiation, light intensity, time and other factors on light-heat conversion, which makes the precise control of light-heat conversion lack basis. In this paper, based on Maxwell-Garnett effective medium theory (MG theory), the equivalent conductivity of the composite material under high-frequency near-infrared light irradiation is analyzed, and then the effective dielectric constant of the nanocomposites is deduced. The influence of light intensity, time and other factors on the conversion of light to heat are discussed in this paper.

Key Words：Graphene/polymer nanocomposites; effective medium theory; near infrared light; photothermal effect; photothermal conversion

目 录

第1章 绪论 1

1.1研究背景 1

1.2研究现状 2

1.3研究内容 3

第二章 石墨烯/聚合物基复合材料光热转化理论模型 4

2.1有效介质理论 4

2.1.1石墨烯介电性能的确定 4

2.1.2 复合材料的等效介电性能 5

2.2 复合材料的吸光特性 7

2.3复合材料的光热效应 7

第三章 数值计算结果及讨论 10

3.1石墨烯/聚合物基纳米复合材料吸光性能分析 10

3.1.1光辐照频率对吸光和消光系数的影响 10

3.1.2石墨烯/聚合物基纳米复合材料的等效介电性能分析 12

3.2石墨烯/聚合物基复合材料的光热效应分析 14

3.2.1石墨烯/聚合物基纳米复合材料的热力学响应行为分析 14

3.2.2光辐照频率对光热效应的影响分析 17

第四章 结论 21

参考文献 22

致谢 24

第1章 绪论

1.1研究背景

自工业革命起，资本主义生产方式逐渐向大机器生产发展，人们开始大规模使用不可再生资源，如：煤，天然气等化石燃料。预计世界对化石燃料的需求（从石油开始）可能会在未来二十年内超过年产量。燃烧的化石燃料释放出有害的排放物，例如二氧化碳，氮氧化物，气溶胶等，这些有害的排放物会影响本地，区域和全球环境。随着环境污染的事件逐渐增加，人们开始越来越关注环境问题，研发新的能源技术，找寻可代替传统化石能源的新型环境友好型可再生清洁能源。在所有可用的可再生能源中，太阳能热能是最丰富的一种，既有直接形式也有间接形式。太阳发出的能量为3.8×10²³kW，其中约60%到达地球表面，其余的被反射回太空并被大气吸收^[1]。每年到达地球表面的太阳辐射比所有估计的（发现和未发现的）不可再生能源（包括化石燃料和核能）大一个数量级。从某种意义上讲，可以说太阳的能量是用之不竭的。综上，太阳能是最经济有效且实用的清洁能源之一。

在太阳光的传播过程中，到达地球附近的只有波长比较长的光，再经过大气层的吸收后，仅有可见光和近红外光能够到达地球表面^[2]。近红外光在太阳光中占比最高，对生物组织具有强穿透能力，在能源、医疗等领域都具有重要的应用价值。但是传统的光能利用途径在该波段利用效率都不高，如：光电效应、光化学反应。相比之下，光热转换在近红外光的利用上更具优势，利用效率更高，光能更容易转换成热能。因此，研究近红外光光热转换材料具有重要价值。