Journal of Nano Research Vol. 23

Abstract: Although titanium dioxide (TiO₂) is an implantable biomaterial with its antibacterial activity, infection on TiO₂ surfaces remains a problem for medical settings. According to our previous studies, curcumin, the main component of turmeric (Curcuma longa), partially hindered the attachment of Streptococcus mutans to human tooth surfaces. Therefore, it was examined whether several implant device-associated bacteria were able to adhere to nanosized TiO₂ surfaces. In addition, the effect of curcumin on the bacterial adhesion was investigated. Bacterial strains were cultured on pure Ti and TiO₂ surfaces with various nanotube sizes in the absence or presence of curcumin and observed by scanning electron microscopy. Consequently, most bacteria adhered to Ti and TiO₂ surfaces. However, curcumin increased the adhesion of bacteria including S. mutans. The results suggest that bacterial adhesion to implant titanium surfaces can be augmented via curcumin ingestion.

Abstract: Melt splitting is a new technique for the mass production of nanofibers. The polymer melt split radially into several hundred very fine filaments in a specially designed nozzle. The prediction model for filament diameter after splitting in the melt splitting process is established based on the surface wave method. The predicted filament diameter compares favorably with the experimental data. Effects of the air pressure and polymer flow rate on the filament diameter are studied. It is found that larger air pressure and smaller polymer flow rate can all produce finer filaments. The results provide a good foundation for the optimization of the melt splitting technique.

Abstract: The major topic covered in this paper is fabrication and performance study of polyacrylonitrile (PAN) ultrafine fibers from high-concentration solutions via a vibration-electrospinning technique. The influences of ultrasonic vibration on the solution properties of high viscous PAN solution as well as surface morphology and mechanical performance of PAN fibrous mats were investigated. The results indicated that: (1) the effect of ultrasonic vibration on the mechanical properties was significant; (2) the vibrorheological effects of ultrasonic vibration appeared not only in dramatic reduction of polymer viscosity, but also in improvement of the electrospinnability of polymer solutions; (3) fibers with smaller diameter, better uniformity and fewer surface defects were prepared with the application of vibration; and (4) the tensile strength of membranes was substantially enhanced at optimized vibration parameters comparing that without vibration treatment.

Abstract: A meso-mechanical constitutive model of TiC particle reinforced titanium matrix composites (TiC/TMCs) under impact loading is established to investigate the mechanical behavior of TiC/TMCs. Based on Eshelbys equivalent inclusion theory and Mori-Tanakas concept of average stress in the matrix, the compliance tensor is formulated. By adding nucleation and growth crack models, the influences of micro-cracks on compliance tensor and damage evolution are examined. Finally, a one-dimensional dynamic constitutive model subjected to impact loading is presented to explore the mechanical behavior of TiC/TMCs.

Abstract: In this work, sphere-like, star-like and rod-like InVO₄ microstructures were synthesized through a facile hydrothermal process without using any organic additives or templates, this gives a new path for convenient synthesis of InVO₄ microstructures with different morphologies. The possible formation mechanisms for the InVO₄ microstructures with different shapes are elucidated. Furthermore, the electrochemical intercalation performances with Li⁺ of the as-prepared InVO₄ samples are investigated. The reversible discharge capacities of sphere-like, star-like and rod-like InVO₄ microstructures were 484.2 mAh g^-1, 551.0 mAh g^-1, and 603.3 mAh g^-1, respectively. The results indicated that the morphologies of InVO₄ products had effect on their electrochemical properties.

Abstract: Differential-difference model equations are often considered as an alternative approach to describing some phenomena arising in heat/electron conduction and flow in carbon nanotubes and nanoporous materials, this is due to the fact that continuum hypothesis is no longer valid. A (2+1)-dimensional nonlinear differential-difference equation with an arbitrary function is introduced and new exact solutions are obtained.

Abstract: A charged jet can be accelerated by an electrostatic field for fabrication of continuous micro/nanofibers. A higher voltage results in smaller nanofibers. However, when the voltage surpasses a threshold value, discontinuous nanomaterials can be fabricated.

Abstract: This paper suggests a new method for fabrication of nanofibers with polymer liquid membrane, which is produced by a metal ring rotating through the polymer solution. The thickness of the produced membrane is thin and suitable for nanomaterial fabrication. In this paper the membrane is to form a polymer bubble by blowing air under the presence of a high electronic field, and multiple jets eject when the bubble is ruptured. The effect of applied voltage on the fiber diameter is studied.