摘要
超黑材料在光学仪器、能量收集等领域具有广阔的应用前景,但是大多数制备方法条件苛刻,更重要的是其力学性能差,限制了作为光吸收层的应用。基于激光加工技术制备多孔模板,通过转印、剥离得到稳定的聚二甲基硅氧烷/碳纳米管(PDMS/CNTs)超黑材料。通过SEM、Raman以及UV-Vis-NIR对材料的结构、表面形貌和吸光性能进行表征;利用红外热成像仪记录样品在太阳光下的表面温度变化,研究其光热性能。结果表明,在激光作用下,模板表面能够形成孔洞结构,通过控制激光功率可以改变孔洞的大小和深度。相应地,通过转印、剥离制备得到的PDMS/CNTs吸光材料具有不同深宽比的有序锥形阵列结构,而且锥形结构表面较为粗糙。吸光材料在200~2 000 nm波长范围内均有较强的吸收能力,吸光率能够超过99%,表面呈现出极度黑色。这一方面归因于CNTs材料的本征吸光特性;另一方面与PDMS/CNTs材料表面的锥形阵列结构相关,通过多次光线反射实现在较宽波段内的减反射并陷光,达到增强吸收的目的。进一步探究PDMS/CNTs超黑材料的耐久性,结果表明,在高温热老化、光老化以及机械外力作用下,其吸光性能基本保持不变。最后,研究了PDMS/CNTs超黑材料的光热性能,在太阳光下,其升温值达到65℃。超黑材料的制备方法简单且稳定性好,在吸光领域将具有很大的应用潜力。
Owing to their excellent light-absorption properties, ultrablack materials have broad application prospects in optical instruments, energy harvesting, and other fields. However, most methods for preparing them involve harsh conditions. More importantly, ultrablack materials exhibit inferior mechanical properties, which limits their application in light-absorbing layers. In this study, a porous template is prepared using laser processing technology, and robust polydimethylsiloxane/carbon nanotube(PDMS/CNT) ultrablack materials are obtained through transfer and peel-off. The structures, surface morphologies, and light absorption properties of the templateare characterized using scanning electron microscopy, Raman spectroscopy, and ultraviolet-visible-near infraredspectroscopy. The surface-temperature change under one-sun irradiation is recorded using an infrared thermal imaging camera to analyze its photothermal performance. The results show that, under laser ablation, a hole structure is formed on the template surface.The energy of laser irradiation vibrates the lattice of the carbon precursor, thus generating localized and instantaneous high temperatures. High temperatures can easily destroy the C-O, C=O, and N-C bonds in the resin, thus causing resin ablation and carbon formation in the holes. The size and depth of the holes can be altered by controlling the laser power. The hole size increases with laser power. As the laser power increases from 10 to 20 W, the hole size increases from 270 to 360 μm. Similarly, by increasing the laser output energy, the hole depth increases with the laser power. When the laser power is 20 W, the hole depth can reach 850 μm.Correspondingly, the PDMS/CNT light-absorbing materials exhibit an ordered, conical array structure of different sizes, and the surfaces of the conical structures are relatively rough. As the laser power increases, the depth-to-width ratio of the conical structure(aspect ratio) increases gradually from 1.6(laser power = 10 W) to 2.1(laser power = 15 W) and 2.8(laser power = 20 W). A high aspect ratio facilitates multiple light reflections and creates light traps. The PDMS/CNT material prepared under 20 W laser power shows strong absorption in the wavelength range of 200-2 000 nm, light absorption exceeding 99%, and an extremely black surface.This is attributed to the intrinsic light-absorption characteristics of the CNT material;moreover, it is related to the conical array structure on the surface of the PDMS/CNT material, which can achieve anti-reflection and light trapping in a wide band through multiple light reflections and enhance light absorption. Thus, the reusability of the template is verified. After the template is reused five times, although the light-absorption performance of the obtained material degrades slightly, its light absorption remains higher than 99% in the wavelength range of 200-2 000 nm. The reusable template further simplifies the preparation process and reduces costs. Subsequently, the durability of the PDMS/CNT ultrablack material is investigated. The result shows that its light-absorption performance remains unchanged under high-temperature thermal aging and photoaging. Moreover, the ultrablack material is mechanically stable and can withstand repeated pressing. The conical surface array is primarily composed of a PDMS elastomer.Owing to its elasticity, the structure can recover after an external force is released. Moreover, after repeated pressing, no black substance is observed on the surface of the adhesive roller. This shows that the intrinsic light-absorbing CNTs are embedded in the PDMS and are stable. Compared with ultrablack materials such as carbon nanotubes and carbon aerogels, PDMS/CNT ultrablack materials are significantly more durable. Finally, the photothermal performance of the PDMS/CNT ultrablack material is investigated.Under one-sun irradiation, the surface temperature increases by 65 ℃ at the maximum. The method for preparing ultrablack materials is simple and offers good stability. Thus, ultrablack materials are highly promising for application in light absorption.
作者
赵伟伟
余文杰
刘小青
ZHAO Weiwei;YU Wenjie;LIU Xiaoqing(Key Laboratory of Advanced Marine Materials,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China)
出处
《中国表面工程》
CSCD
北大核心
2024年第6期473-480,共8页
China Surface Engineering
基金
国家自然科学基金(52003282)
中国科学院宁波材料技术与工程研究所所长基金(2022SZKY0311)。
关键词
超黑
激光加工
微纳结构
吸光性能
耐久性
ultrablack
laser processing
nano-micro structure
light-absorption property
durability
作者简介
赵伟伟,女,1990年出生,博士,副研究员,硕士研究生导师。主要研究方向为树脂基碳材料。E-mail:zhaoweiwei@nimte.ac.cn;通信作者:刘小青,男,1980年出生,博士,研究员,博士研究生导师。主要研究方向为新型树脂材料的合成与改性。E-mail:liuxq@nimte.ac.cn。
