曹化强
论文题目：一维纳米材料有序阵列的制备和结构
作者简介：曹化强，男，1965年07月出生，1999年03月师从于南京大学徐正教授，于2001年06月获博士学位。
摘 要
纳米材料是指在三维空间中至少有一维处于纳米尺寸范围或由它们作为基本单元构成的材料。纳米材料不仅在诸多领域具有潜在的技术应用前景，而且搞清在体材料和分子材料间性质的转变方面具有十分重要的学术意义。一维纳米材料则是指在空间有两维处于纳米尺度，如纳米线，纳米管等。在纳米科学技术的基础上发展起来的新型量子器件则是当前科学技术研究的热点和前沿之一。它包括设计，研究和制作新一代的量子器件，并探讨新型量子器件在激光技术，信息存储及运算技术上的应用。纳米技术是一种人工独特的结构技术，是受量子论支配的。被称为21世纪的三大尖端技术的信息科学技术，生命科学技术与纳米科学技术，它们的技术关键都是由量子效应决定的，因此，纳米技术的应用有可能引发信息革命，生物工程革命。
现在，人们关注的焦点是纳米组装体系。美国加州大学洛伦兹伯克力国家实验室的科学家在Nature上发表论文指出：纳米尺度的图案材料是现代材料化学和物理学的重要前沿课题。
由于一维体系是可用于有效的电子输运和光激发的最小的微结构。被认为是纳米级装置的功能和集成的关键所在。然而，人们对其性质却知之甚少。因此，如何将原子及其他构件合理地组装成纳米级直径的一维结构？以及这些量子线的本征性质是什么？这些性质与直径和结构的关系是怎样的？就成为人们需要弄清的核心问题。
尽管，人们已经对一维纳米结构的许多方法进行过探索，但至今还没有合成一维纳米结构的通用的方法。在众多的合成纳米材料的方法中，由C. R. Martin等人扩展的“模板合成法”被证明是一种有价值的制备纳米材料的方法。使用这种方法可以制备金属，半导体，聚合物等各种成分组成的纳米线和纳米管，这些材料具有新颖的光学，电子和磁性等性质。本论文包括两个部分：富勒烯（C60和C70），金属硫化物（半导体）等纳米线阵列的合成与表征；纳米管（聚合物和碳纳米管）包装金属纳米线阵列的合成，表征与磁性研究。
1， 首次采用溶胶-凝胶法在多孔氧化铝模板孔道内制备富勒烯纳米线阵列，纳米线直径约在60-300纳米范围内，长度约为60微米，相当于模板的厚度。C60和C70纳米线均为单晶结构。C60纳米阵列的UV-vis吸收光谱在230，276和364纳米处有较宽的吸收峰，与C60溶胶的吸收光谱相比，产生了明显的红移，这是由于C60粒子长大的缘故。
2， 采用溶胶-凝胶法在多孔氧化铝模板孔道内制备出CdS纳米阵列，纳米线的直径为100-300纳米，长度约为60微米，为单晶结构。
3， 采用两步合成法在多孔氧化铝模板孔道内制备出聚合物纳米管包装金属纳米线（Fe, Co, Ni）阵列：首先在多孔氧化铝模板孔道内利用聚合反应合成出聚合物纳米管，作为“二级模板”，再利用电化学沉积方法在“二级模板”内合成金属纳米线，从而得到聚合物纳米管包装金属纳米线阵列（相应表示为APF, APC, APN）。利用XRD和SEM对该阵列进行形貌和结构的研究，并用VSM对其磁行为进行研究，APF的矫顽力为119-210Oe， APC的矫顽力为180-209Oe, APN的矫顽力为129-180Oe，可开发作为高密度磁记录材料，聚合物纳米管还对金属纳米线起到保护作用，使之免受腐蚀，从而使该材料具有实际应用意义。
4， 采用三步合成法在多孔氧化铝模板孔道内制备出碳纳米管包装金属纳米线（Fe, Co, Ni）阵列：头两步同3，然后对聚合物纳米管包装金属纳米线在氩气氛中进行石墨化，得到碳纳米管包装金属纳米线阵列（相应表示为ACF, ACC, ACN），利用XRD , SEM, TEM，HRTEM和Raman光谱对该阵列进行表征，并用VSM对其磁行为进行研究，ACF的矫顽力为191.2Oe，ACC的矫顽力为181.4Oe，ACN的矫顽力为116.8Oe。该法得到碳纳米管包装金属纳米线有序阵列复合结构具有金属填充率高，金属纳米线连续，均匀等优点，且碳纳米管的直径和壁厚可以调节。开辟了一条合成碳纳米管包装其他材料的简易方法。该复合结构可开发作为高密度磁记录材料。
关键词：一维，纳米材料，有序阵列，制备，结构
Preparation and Structure of
Array
of One-Dimensional
Nanomaterials
ABSTRACT
Nanomaterials have at least
one-dimensional size in the range of nanometer scale. Materials with nanoscopic
dimensions not only have potential technological applications in areas such as
devices technology and drug delivery but also are of fundamental interests.
One-dimensional nanomaterials have a radial size in the range of nanometer,
such as, nanowires and nanotubules, etc. The new quantum-devices based on
Nano-ST are the focus of the current study of science and technology. It includes
design, study and preparation of new quantum devices in the laser technology,
information storage technology and operation technology. Nanotech is based on
the artificial quantized structures technology, which was controlled by the
quantum theory. 21th century is called as “the Era of Photo”, “the Era of
highly information” and “the Era of Biological Engineering”, etc, but the key
of these is quantum effect. So, we think the application of nano-ST will
initiative the revolution in information field and biological engineering
field.
Now, people have been paying
great attention on the nano-assembly system. The scientist in Lawrence Berkeley
National Laboratory at University of California at Berkely, point out on Nature that: nano-size pattern materials
are the key problems in the field of modern materials-chemistry and physics.
1D systems are the smallest
dimensions structures that can be used for efficient transport of electrons and
optical excitation, and are thus expected to be critical to the function and
integration of nanoscale devices. However, little is known about the nature of
the 1D nano-system. Interest in nano-structures has been driven by fascinating
questions: (i) how can nanostructures controlled dimensionality and size be
rationally synthesized or fabricated and (ii) what are the intrinsic and
potentially unique physical properties of nanostructures?
Although a number of
strategies have been pursed, general methods for the growth of 1D
nanostructures have not been available. Among numerous chemical methods for
preparing nanomaterials, “template synthesis method” explored by C. R. martin et al. has been proved to be a versatile
approach for preparing nanomaterials. Using this method, nanotubules and
nanofiblis composed of metals, semiconductors, polymers and various composites
of these materials were prepared and these materials often have useful optical,
electronic and magnetic properties. This dissertation includes two parts:
preparation and characterization of array of fullerene and metal sulfide
nanowires and preparation and characterization of array of polymer and carbon
nanotubules filled with metal nanowires and the study of their magnetic
behavior. The main results are as follows:
1. Using sol-gel
method, array of fullerene (C60 and C70) nanowires in the
pores of porous alumina template membrane was prepared. C60 and C70
nanowires with diameters of 100-300 nm is composed of single crystals. And the
longest length of fullerene nanowires is equal to the thickness of alumina
template. There are three broad bands appeared at 230, 276 and 364 nm of C60
array which is similar to the C60 sol (215, 259 and 340 nm), but has
significant red shifts.
2. We use sol-gel
chemistry to prepare semiconductor CdS nanowires within the pores of porous
alumina template membrane. CdS nanowire with diameters of 100-300 nm, and
length in 60 mm, is composed of
single crystal CdS.
3. An array of metal
(Fe, Co, Ni) nanowires filled within polyaniline nanotubules was obtained using
a two-step templae synthesis method. First, an array of polyaniline nanotubules
was synthesized in the pores of porous alumina template membrane by
polymerization, then it was used as a “second-order template” for
electrochemistry deposition metal within the polyaniline nanotubules, which was
characterized by SEM and XRD. Their magnetic behavior was studied by VSM, and
the data shown that they may be promising candidate for high-density magnetic
recording materials with coercive forces range from 119 to 210 Oe for APF, 129
to 180 Oe for APN, and 180 to 209 Oe for APC.
4. An array of metal
(Fe, Co, Ni) nanowires filled with carbon nanotubules was obtained using
three-step template synthesis method. The first two steps just as 3, then the
graphitization of polyaniline nanotubules filled with metal were carried out by
heat-treatment at different temperature under argon for a period of 30 min~30
h. The carbon nanotubules filled with metal were characterization by SEM, TEM,
XRD and Raman spectra. The magnetic behavior of these materials was studied.
The data, coercive forces 191.2Oe for ACF，181.4Oe for ACC， 116.8Oe for ACN,
shown that it may be a promising candidate for high-density magnetic recording
materials.
KEY WORDS:
one-dimensional, nanomateials, array, preparation, structure
