【作者】 鲁兵安；

【导师】 谢二庆；

【作者基本信息】 兰州大学 ， 电子材料， 2012， 博士

【摘要】 人类发展面临着重大的挑战,纳米材料对解决人类面临的一些挑战具有重要的作用,电纺丝作为一种制备纳米材料的简单方法,受到了广泛的关注。但是电纺丝工业化过程中受到了产率低,产物单一,实际应用较少等阻碍了其工业化的发展。本论文中基于电纺丝做了以下工作。(1)提出了一种新型的静电纺丝装置,此装置是用一个旋转的金属锥作为喷头,纺丝过程中溶液旋涂在锥体表面。在旋转过程中液体受到外力会形变,后在静电作用力下转化为纳米纤维。产率达到了10g/min,较传统的电纺丝产率提高了近1000倍。详细的研究了纳米纤维的形成机制,研究了不同因素对纳米纤维的影响。这为电纺丝工业化生产提供了的新的方法与可能。(2)提出了一种新的高产率低成本的制备纳米材料的方法。此种方法能够直接制备活细胞掺杂的纳米纤维。此种方法是通过高气压将液体通过微米孔压入空气中形成具有极高速率的微米液滴,液滴在温度场中高速运动过程中形变拉伸,从而形成了纳米纤维或者纳米管。实验中单个喷嘴的速率达到了10g/s。更重要的是,此种方法可以极大的提高活细胞在纤维中的成活率,可以广泛的应用于生物工程等。(3)通过调节W/O静电纺丝过程中收集板的温度制备了碳纳米管和纳米带。纳米管的内径为25-50纳米,外径为50-100纳米,壁厚为10-50纳米。同时制备了纳米带其长度为微米级,厚度为1-5纳米,宽度为100-300纳米。详细讨论碳纳米管和纳米带的形成机制。形成纳米管的这种技术可能被应用于制备多壁,甚至单壁的碳纳米管,形成纳米带的这种技术可能应用于制备石墨烯。(4)用自组装的方法合成了一种具有厚度小于10nm的新型碳材料——碳纳米节,该纳米节生长在非晶碳纤维上。实验中发现,在空气中,220℃预氧化,和在1×10-4pa,750℃高温真空退火过程中碳纳米节可以通过自组装得到。并对碳纳米节的生长机理给予了研究,提出了可能的生长机理。根据生长机理,设计了实验,让纳米节可控的生长,也从侧面验证了我们的生长理论。这种新的制备方法,为碳纳米材料的应用提供了新的方式。(5)制备了一种具有多孔结构的二氧化钛纳米管。多孔二氧化钛纳米管的直径为200nm左右,其上孔洞分布均匀,孔洞的直径分布在10nm左右,XRD与TEM等证明其为混合相的混晶结构。并将其应用于光催化上,发现多孔二氧化钛纳米管具有良好的光催化性能,详细研究了其结构和形貌等对光催化性能的影响。为大规模的工业化应用提供了可靠的保证。用传统的电纺丝制备氧化锌空心纳米球,详细的研究了其可能的生长机制。后对其形貌和结构进行了表征。发现空心氧化锌纳米球是由颗粒状组成的颗粒球。并将其应用与光催化上,发现空心氧化锌纳米球具有良好的光催化性能,详细研究了其结构和形貌等对光催化性能的影响。(6)采用氧化还原方法制备了石墨烯,然后采用静电纺丝方法,制备了石墨烯掺杂的壳聚糖-聚乙烯醇纳米纤维。并将该纳米纤维薄膜应用于伤口愈合。实验证明,含有石墨烯的壳聚糖-聚乙烯醇纳米纤维有利于伤口的愈合。也提出了石墨烯有利于伤口愈合的可能机制。这种含有石墨烯的壳聚糖-聚乙烯醇纳米纤维可以直接应用于工业化生产,为市民的健康提供一定的帮助。更多还原

【Abstract】 Human development facing some challenges, nano-materials plays an important role to solve the challenges. Electrospinning has received extensive attention as a simple way of nanomaterials. Electrospinning process of industrialization by the low throughput, the practical application of less hindered the development of its industrialization. In this thesis, based on electrospinning, we do the following things:(1) A needle less electrospinning setup using an electriferous rotating cone as the spinneret. The production throughput of this approach was about10g/min, which was several thousand times higher than that by traditional electrospinning technique. Additionally, the effects of electrospinning speed and the voltage between the cone and the collector of this electrospinning system on the properties of the fibers are discussed. The improvement of this method might open new doors to many potential industrial applications of electrospinning technique.(2) A novel method is reported of producing nanofibers/nanotubes (measuring from tens of nanometres to several hundreds of nanometres) containing living cells, mechanically and with ultrahigh speed and at low cost. We has demonstrated that the throughput of this spinning method to fabricate nanofibers/nanotubes from an individual setup could be as high as10g/s. A possible mechanism for this extrusion method was proposed based on flow mechanics and the experimental results. Additionally, it was demonstrated that the living cells with high survival rate can be used in bioengineering.(3) Carbon nanotubes and carbon nanobelts were obtained via electrospinning on a basis of W/O emulsion technique, respectively.The carbon nanotubes has the inner diameter of25-50nm and the outer diameter of50-100nm and the wall thickness of10-50nm, and the width and thickness of the nanobelts range from100to300nm, and1to5nm, respectively. A slight difference of bonding configuration of the carbon nanofibers, carbon nanotubes and carbon nanobelts is attributed partly to their different topological structures. The novel method is versatile and could be extended to the fabrication of various types of nanotubes and nanobelts.(4) A novel structure of carbon nanonodules containing fewer than10layers graphene has grown on amorphous carbon nanofibers by carbonization-induced self-assembly. It is found that a successive processes containing pre-oxidation in air at220℃and carbonization in a high vacuum1×10-4pa and at750℃are necessary for the fabrication of the carbon nanonodules. It is also found that the temperature of the collector during electrospinning of the fiber and the pressure of carbonization are critical factors for growth of the nanonodules. With these mechanisms, carbon nanonodules can be selectively grown on the prepared amorphous carbon nanofibers using pre-oxidation and carbonization of an electrospun glycerol-polyacrylonitrile fiber.(5) Highly porous TiO2nanotubes were prepared by emulsion electrospinning. The mixed crystalline material comprised anatase and rutile TiO2particles, whose diameters were about11nm and21nm, respectively. The highly porous TiO2nanotube were shown to have excellent catalytic activities. The new method for producing highly porous TiO2nanotubes is versatile and could be extended to the fabrication of various types of highly porous nanotubes.Using a classical electrospinning and subsequent thermal treatment technique to successfully fabricate hollow ZnO nano-spheres. The hollow ZnO nano-spheres were then used to study the degradation of Rhodamine B (RhB) dye and were proven to have excellent photocatalytic activity. The mechanism of formation of hollow ZnO nano-spheres and the reason for the high photocatalytic activity were also investigated.(6) Using electrospinning preparation of chitiosan-PVA nanofibers contains graphene. The nanofibers can be directly used in wound healing, and find graphene as an antibacterial material can beneficial to wound healing. The possible mechanism for graphene as an antibacterial material beneficial to wound healing is presented.更多还原