Some Experiments In Eiectrospinning

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.