Free-standing carbon nanotube-titania photoactive sheets.

We report on the development of a new photoactive material via titania (TiO2) nanoparticle deposition on free-standing aligned carbon nanotube (CNT) sheets. Controlling homogeneous dispersion of negatively charged TiO2 nanoparticles, achieved by adjusting pH higher than the point of zero charge (PZC), influenced electrochemical deposition of TiO2 on CNT sheets substrate. Varying deposition time with constant voltage, 5 V allowed different thickness of TiO2 to be deposited layer on the CNT sheets. The thickness and morphology of CNT-TiO2 sheets was verified by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Electrochemical experiments show that diffusion coefficient of Fe(CN)6(3-) was 5.56×10(-6) cm(2) s(-1) at pristine CNT sheets and 2.19×10(-6) cm(2) s(-1) at the CNT-TiO2 sheets. Photocatalytic activity for CNT-TiO2 sheets exhibits high photocurrent density (when deposition time=30 min, 4.3 µA cm(-2) in N2, 13.4 µA cm(-2) in CO2). This paper proved a possibility to use CNT-TiO2 sheets based on highly-aligned CNT sheets substrate as new photoactive material.

Recent advances on the development of magnesium alloys for biodegradable implants.

In recent years, much progress has been made on the development of biodegradable magnesium alloys as "smart" implants in cardiovascular and orthopedic applications. Mg-based alloys as biodegradable implants have outstanding advantages over Fe-based and Zn-based ones. However, the extensive applications of Mg-based alloys are still inhibited mainly by their high degradation rates and consequent loss in mechanical integrity. Consequently, extensive studies have been conducted to develop Mg-based alloys with superior mechanical and corrosion performance. This review focuses on the following topics: (i) the design criteria of biodegradable materials; (ii) alloy development strategy; (iii) in vitro performances of currently developed Mg-based alloys; and (iv) in vivo performances of currently developed Mg-based implants, especially Mg-based alloys under clinical trials.

A multi-wall carbon nanotube tower electrochemical actuator.

Patterned multiwall carbon nanotube arrays up to four millimeters long were synthesized using chemical vapor deposition. Electrochemical actuation of a nanotube array tower was demonstrated in a 2 M NaCl solution at frequencies up to 10 Hz with 0.15% strain using a 2 V square wave excitation. The synthesis and electrochemical modeling approach outlined in the paper provide a foundation for the design of nanotube smart materials that actuate and are load bearing.