Papers by Keyword: Templating

Abstract: Nanoporous carbon was successfully prepared by using polybenzoxazine synthesized from bisphenol-A, melamine and formaldehyde as a precursor. The varied HCl amounts have been added into the pre-polymer solution as a catalyst for the ring-opening polymerization. The reaction was traced by FTIR and DSC. In addition, the degradation behavior was studied by TGA and the textural properties were characterized by SEM and surface area analysis (AS1-MP). The nanoporous carbon obtained showed the highest char yield up to 48%. The interconnected structure from the SEM images of the nanoporous carbon exhibited significantly high surface area of 632 m²/g, high total pore volume up to 1.78 cm²/g, small average pore diameter and narrow pore size distribution detected by AS1-MP. After the activation process, the surface area has been drastically improved leading to the increasing of surface area and total pore volume up to 1119 m²/g and 1.93 cm²/g, respectively. In order to further study on the enhancement of surface area, NaCl, a water soluble compound, has been used as a template. As a result, the surface area has been improved up to 1516 m²/g.

Abstract: In order to mimic natural tissues, a successful strategy is to design bio-inspired materials including controlled morphological and biochemical cues as nature guidelines suggested. In this context, old and new process technologies, case by case, have to be adapted to develop innovative templates with the finest control of structural/functional properties able to correctly interact with biological tissues. Since organic and inorganic materials from synthetic or natural source do not singularly satisfy all the requirements, the discovery of new process solutions able to combine two or more materials into multicomponent systems (i.e., blends, composites, hybrids) may represent an interesting alternative for scaffold design. In order to simplify process conditions, without limiting the complexity of final device, current trends mainly address to bottom up approaches based on fibres used as micro-tassels, variously combined as a function of the desired properties – biochemical, mechanical or biological ones, to form the final device.Here, two different approaches based on the use of polymeric fibres have been proposed. Continuous microfibres processed by capillary extrusion can be integrated as reinforcement agent of porous biodegradable matrices to develop composite scaffolds with multiscale degradation properties suitable for hard tissue regeneration. Alternatively, micro-or submicro-fibres made of synthetic and/or natural polymers can be randomly assembled or patterned to form uniaxially oriented or textured platforms, thanks to the high customization of electrofluidodynamic techniques (i.e., electrospinning). Both approaches offer a large variety of micro and nanostructured platforms - with micro/nanoscale architecture and peculiar chemical composition - suitable as scaffolds or biotextiles for tissue regeneration or other biomedical uses.

Abstract: This paper is focused on the preparation and characterization of different lamellar silica prepared by liquid crystal templating and silanisation. The initial template can be removed and replaced in the interlamellar spaces by different types of silane, being covalently grafted to the solid by reaction with the surface silanols. The lamellar stacking periodicity remains after this modification. The surfactant extraction can lead in significant grafting of isopropanol if the solid is simply refluxed in isopropanol, which have the effect of preserving the periodicity of the lamellar stacking. The surfactant extraction in an Soxhlet equipment avoid this reaction, with the effect of platelets organization collapsing. The lamellar silica studied exhibit great specific surface and combination of meso and microporosity, making them interesting materials for nanocomposite or catalysis applications.

Abstract: Monodispersed ZrO2 (includes 8mol % Y2O3) precursor nanoparticles, which were well dispersed in aqueous solution, were successfully synthesized. The as-synthesized ZrO2 precursor nanoparticles were homogenously coated on the surface of polystyrene particles. Multilayer coating process was successfully implemented by using polyacrylic acid (PAA) to modify the surface charges of the coated particles, which was characterized by zeta-potential, particles size distribution and scanning electron microscopy (SEM).

Abstract: Using appropriate electrodeposition conditions, it is shown that the structural and magnetic properties of arrays of Co and CoCu/Co nanowires can be controlled. The hcp c axis orientation can be oriented parallel or perpendicular to the wire axis simply by changing the pH of the electrolytic solution and/or deposition rate. This selected orientation of the c axis leads to a drastic change in overall magnetic anisotropy and is promising for the fabrication of spin valves structures by electrodeposition.