No abstract

In this study, bio-based phase change material (bio-PCM) was successfully encapsulated in ultrafine fibers via coaxial electrospinning technique. Natural soy wax was used as the bio-PCM for thermal storage and Polyurethane (PU) was used as the shell material for encapsulation. The bio-PCM fibers were characterized by environmental scanning electron microscopy (ESEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and X-ray Diffraction (XRD). The results indicate that coaxial electrospinning resulted in a uniform fiber morphology with a core-shell structure, and a homogeneous wax distribution throughout the core of the fibers. Thermal analysis results show that the enthalpy increases with wax content. The fibrous structures exhibited balanced thermal storage and releasing properties for thermo-regulating functions. The thermal properties were unaltered after 100 heating-cooling test cycles, demonstrating that the composite fibers have good thermal stability and reliability.

Well-defined 3D Fe(3)S(4) flower-like microspheres were synthesized via a simple biomolecule-assisted hydrothermal process for the first time. On the basis of a series of contrast experiments, the probable growth mechanism and fabrication process of the products were proposed. The electrical conductivity property of the as-synthesized Fe(3)S(4) sample exhibited a rectifying characteristic when a forward bias was applied for the bottom-contacted device. The magnetic properties of the products were studied as well and the results demonstrated that the products presented ferromagnetic properties related to the corresponding microstructure. In addition, we first verified that the Fe(3)S(4) flower-like microspheres could store hydrogen electrochemically, and a discharge capacity of 214 mA h g(-1) was measured without any activation under normal atmospheric conditions at room temperature.

The objectives of this work are twofold. Firstly, while most work on electrospinning is limited to the development of only functional materials, a structural application of electrospun nanofibers is explored. Secondly, a drug-loaded tissue suture is fabricated and its various properties are characterized. Braided drug-loaded nanofiber sutures are obtained by combining an electrospinning process with a braiding technique followed by a coating procedure. Two different electrospinning techniques, i.e. blend and coaxial electrospinning, to incorporate a model drug cefotaxime sodium (CFX-Na) into poly(L-lactic acid) (PLLA) nanofibers have been applied and compared with each other. Properties of the braided drug-loaded sutures are characterized through a variety of methods including SEM, TEM and tensile testing. The results show that the nanofibers had a preferable micromorphology. The drug was incorporated into the polymer nanofibers homogeneously, with no cross-linking. The nanofibers maintained their fibrous structures. An in vitro release study indicates that the drug-loaded nanofibers fabricated by blend electrospinning and coaxial electrospinning had a different drug release behavior. An inhibition zone experiment shows that both sutures obtained from the nanofibers of the different electrospinning techniques had favorable antibacterial properties. The drug-loaded sutures had preferable histological compatibility performance compared with commercial silk sutures in an in vivo comparative study.