【作者】 牛丽娟；

【导师】 陈彧；

【作者基本信息】 华东理工大学 ， 先进材料与制备技术， 2011， 硕士

【摘要】 非线性光学的重要应用之一是光限幅。光限幅材料和器件主要用于保护人眼,光学元件和光学传感器不受强激光脉冲的损害。优越的光限幅器不仅可以很大程度削弱具有潜在危害的强激光束,同时对周围低强度的光线具有较高的透过率。基于碳纳米管的功能材料在可见光到近红外区域具有优越的广谱光限幅响应。但是碳纳米管本身溶解性差和不易加工的缺点阻碍了碳纳米管的应用。高分子功能化的碳纳米管材料不仅具有较好的溶解性且在实际光限幅应用中更易加工成薄膜及相应器件,因此,对碳纳米管进行共价高分子修饰是一项很有学术意义和实践价值的课题。本文通过不同的方法制备了几种高度可溶的新颖高分子/碳纳米管杂化材料,对杂化材料的基本结构及非线性光学（含光限幅）性能进行了初步研究。第一章综述了碳纳米管悬浮液,可溶碳纳米管,小分子掺杂碳纳米管和高分子/碳纳米管杂化材料的光限幅性质。其中,碳纳米管悬浮液的光限幅机理主要是热诱导产生的溶剂气泡和碳纳米管升华引发的非线性散射,而可溶碳纳米管的光限幅机理则更为复杂第二章中利用共轭高分子PCBF-NH2制备了共价功能化MWNT-PCBF杂化材料。通过杂化材料MANT-PCBF的N1s XPS谱图,在402eV出现的新峰归属于与羰基C原子相连的N原子（如,NH-C=O）,说明高分子通过共价键成功的接枝在MANTs表面。PCBF-NH2在532nm处只显示很弱的光限幅响应,而MWNT-PCBF杂化材料的Z-扫描结果表明共价修饰后MWNTs在532和1064 nm处都具有更宽的低透过率和散射现象。第三章以表面带有负电荷的SWNTs为阴离子聚合引发剂实现了PVK在SWNTs上的原位生长,所制备的PVK修饰SWNT杂化材料表现出高度可溶性。在相同的线性透过率下,和原始SWNT相比SWNT-PVK悬浮液具有更好的光限幅行为,是制备光限幅器的理想材料。微等离子体和微气泡诱导的非线性散射被认为是SWNT-PVK杂化材料主要的光限幅机理。第四章中利用Suzuki反应合成了侧链带有醛基的共轭高分子PFC-CHO,之后通过简单的1,3-偶极环加成反应将高分子接枝在MWNTs表面得到可溶的MWNT-PFC杂化材料。和原始MWNTs的拉曼光谱图相比,接枝高分子后MWNT-PFC杂化材料的I_D/I_G值比增大,说明有大量的sp²杂化态碳转化为sp³杂化态,高分子成功的接枝在MANTs表面。第五章通过硝化反应制备PVK-NO₂,还原后得到带有氨基的高分子PVK-NH₂。高分子PVK-NH₂通过酰胺化反应修饰MWNTs,得到溶解性好的MWNT-PVK杂化材料。高分子接枝在MWNTs上之后,MWNT-PVK的红外光谱图中1706cm^-1处的峰归属于酰胺键的伸缩振动峰,说明高分子成功的接枝在MANTs表面。更多还原

【Abstract】 Optical limiting is an important application of nonlinear optics, useful for the protection of human eyes, optical elements, and optical sensors from intense laser pulses. An optical limiter is such a device that strongly attenuates high intensity light and potentially damaging light such as focused laser beams,whilst allowing for the high transmission of ambient light. CNTs-based functional materials exhibit a broadband optical limiting response covering the visible to infrared region. But for CNTs, the lack of solubility and their difficult manipulation in any solvent have, imposed great limitations on their use. Many efforts have currently been invested into design and prepare soluble CNTs functionalized with polymers, which improve solubility and allow for the fabrication of films, coatings, or suspensions required for the use of nanotubes in a real optical limiting application.In the first Chapter, the optical limiting properties of carbon nanotube suspensions, solubilized carbon nanotubes, small molecules doped carbon nanotubes and polymer/carbon nanotube composites have been reviewed. The optical limiting responses of carbon nanotube suspensions are shown to be dominated by nonlinear scattering as a result of thermally induced solvent-bubble formation and sublimation of the nanotubes, while the solubilized carbon nanotubes optically limit is more complex.In the second Chapter, a novel MWNTs covalently functionalized with conjugated polymer PCBF-NH2, was synthesized. In the N1s XPS spectrum of MWNT-PCBF, an appearance of new peak at 402 eV corresponding to N bound to the carbonyl C (i.e., NH-C=O), which provides essential and useful information for the covalent attachment of the polymer onto the surface of MWNTs. Unlike PCBF-NH2, which only displayed a weak optical limiting response at 532 nm, Z-scan for MWNT-PCBF exhibited a much broader reduction in transmission and a scattering accompanying on the focus of the lens at both 532 nm and 1064 nm, indicating a prominent broadband optical limiting response. The thermally induced nonlinear scattering is responsible for the optical limiting.In the third Chapter, a new poly(N-vinylcarbazole)-covalently grafted single-wall carbon nanotubes(SWNT-PVK) hybrid material was synthesized by an in situ anionic polymerization reaction of N-vinylcarbazole and the negatively charged SWNTs. Incorporation of the PVK moieties onto the SWNTs surface considerably improves the solubility and processability of SWNTs. At the same level of linear transmission, the SWNT-PVK dispersions show better optical limiting performance than the pristine SWNT dispersions, which manifest this material a suitable candidate for viable optical limiting devices. Micro-plasmas and/or micro-bubbles induced nonlinear scattering is considered as the main mechanism for optical limiting.In the forth Chapter, a new conjugated polymer PFC-CHO with pendent aldehyde groups in the polymer sidechains was synthesized by the Suzuki coupling reaction. Then, the polymer was successfully added to the MWNT surface via a simple 1,3-dipolar cycloaddition reaction to give a soluble MWNT-PFC hybrid material. In contrast to the Raman spectrum of MWNTs, the D-to G-band intensity ratio (ID/IG) for MWNT-PFC increased, which provides useful information for the attachment of the polymer onto the surface of MWNTs.In the last Chapter, we used polymer PVK to prepare PVK-NH2,which was reacted with MWNTs with surface-bonded acryl chloride moieties to give a soluble MWNT-PVK hybrid material. The stretching mode of an amido bond at 1706 cm(vNH-C=O) was detected in the IR spectrum of MWNT-PVK, which provides useful information for the attachment of the polymer onto the surface of MWNTs.更多还原