Nanoscale & Nanoscale Advances Blog

Implantable medical devices of the future could be built from a new material that is made by layering bacterial cellulose hydrogels with conducting polymers.

Bacterial cellulose (BC) is a naturally occurring polymer hydrogel that is flexible and known to respond to environmental changes. Guang Yang and co-workers at Huazhong University of Science and Technology in Wuhan, China, added a layer of conductive polymer polyaniline (PAni) onto a BC hydrogel to give a material that responds to electrical signals.

The base cellulose hydrogel is made by Gluconacetobacter xylinum bacteria. After purification, the hydrogel is soaked for 48 hours in a solution of salts and aniline monomers. The gel is then sandwiched between two electrodes, and applying an electrical current causes the monomers to form a polymer film layer.

Interested to know more? Read the full news article by Cally Haynes in Chemistry World here…

Read the article by Zhijun Shi, Ying Li, Xiuli Chen, Hongwei Han and Guang Yang in Nanoscale:

Double networks bacterial cellulose hydrogel to build a biology–device interface
Zhijun Shi, Ying Li, Xiuli Chen, Hongwei Han and Guang Yang
DOI: 10.1039/C3NR05214A, Paper

Scientists have designed a grid of light responsive colloidal particles to function as pixels that could be used to create barcodes for cryptographic data storage.

Photochromic dyes are used in films to respond to light, for example in self-dimming sunglasses. These dyes have two isomers, one forms in visible light and is transparent, the other forms in UV light and absorbs light, darkening the sunglasses. If a photochromic dye is placed in a film with a fluorescent dye, and the wavelength of the fluorescence is matched to that absorbed by the photochromic dye, the photochromic dye can be used to switch the fluorescence off and on when exposed to UV or visible light.

Clemens Weiß and his colleagues at the Max-Planck Institute for Polymer Research in Germany, have devised a way to use this kind of light triggered dye switch to store data. Encapsulating the photochromic/fluorescent dye pair inside polymer colloids traps the molecules together prolonging the lifetime of the ‘on’ or ‘off’ state for several days. Assembling these functional colloids within a monolayer of larger colloids creates a grid of fluorescent ‘colloidal pixels’. Shining UV light on chosen areas of the grid turns the pixels’ fluorescence off creating dark areas on the grid whilst leaving others fluorescent.

Interested to know more? Read the full news article by Emily Skinner in Chemistry World here…

Read the article by K. Bley, N. Sinatra, N. Vogel, K. Landfester and C. K. Weiss in Nanoscale:

Switching light with light – advanced functional colloidal monolayers
K. Bley, N. Sinatra, N. Vogel, K. Landfester and C. K. Weiss
DOI: 10.1039/C3NR04897G, Paper

Graphene could find use in next-generation flexible electronic devices thanks to scientists in Taiwan and the US who have developed a low cost and scalable method to pattern graphene onto 3D surfaces.

Flexible electronics are destined to transform the way we manufacture and interact with electronic devices. Graphene’s high electrical conductivity and mechanical stability could prove beneficial in flexible electronic circuits. However, despite its potential, graphene is typically only produced and patterned in research environments with economic barriers hampering its use in commercial applications.

Now, a group led by Mario Hofmann at National Cheng Kung University have demonstrated an easy and scalable approach to depositing high resolution graphene patterns onto surfaces.

Interested to know more? Read the full news article by Michael Parkin in Chemistry World here…

Read the article by Mario Hofmann, Ya-Ping Hsieh, Allen L. Hsu and Jing Kong in Nanoscale:

Scalable, flexible and high resolution patterning of CVD graphene
Mario Hofmann, Ya-Ping Hsieh, Allen L. Hsu and Jing Kong
DOI: 10.1039/C3NR04968J