Issue 9 Chemical Technology 2005

Cover image for Highlights in Chemical Technology

Chemical technology news from across RSC Publishing.

Issue 9

False teeth

A team of US and British scientists has made a material which is similar in structure to tooth enamel, the hardest tissue in the human body. The material is made of calcium phosphate and resembles enamel because of its arrangement of well-aligned crystals into bundles. Henry Margolis from the Forsyth Institute, Boston, and colleagues have discovered that the use of an organic surfactant is important in the process and that the bundles are formed when the solutions are highly viscous. This insight into the conditions needed to form enamel-like structures improves our understanding of the formation of biominerals in living organisms.

Integrated logic gates

Molecular scale logic gates are needed for many nanoscale electronic and photonic devices, but so far most of these logic gates only work in solution. Now an international team of scientists led by Gareth Redmond at the Tyndall National Institute in Cork, Ireland, have made a molecular photonic logic gate by integrating electrical and chemical switching functions into molecules attached to the surface of a nanocrystalline TiO2 electrode. The device acts as a NOR logic gate and responds to both electrical and chemical input.

Robotic sensor selection

Wolfgang Schuhmann and colleagues at Ruhr-Universit�t Bochum, Germany, have come up with a fast and automated way of selecting effective electrocatalysts for nitric oxide sensors. They used a robotic device with an easily movable assembly of electrodes to screen a library of 83 different metalloporphyrins. The effectiveness of each potential metalloporphyrin electrocatalyst was rapidly and reproducibly tested, helping to identify features of some metalloporphyrins that make them well-suited to use in nitric oxide microsensors.

Something to Bragg about

A team of US scientists led by Christopher Li of Drexel University, Philadelphia, has made a Bragg reflection grating which changes its spacing and diffraction efficiency on heating. It is made by holographic photopatterning of a mixture of semi-crystalline polymer (polyethylene glycol) and resin, producing a sub-micron-scale layered structure which could be used to build multifunctional photonic components. The fully-reversible thermal switching is caused by melting and formation of polymer crystals, controlled by changing the molecular weight of the polymer.