An optically active flexible polymeric film with embedded silver nanoparticles has been synthesised by scientists in the US.

George Chumanov, Igor Luzinov and colleagues from Clemson University have shown that it is possible to combine capillary force lithography (CFL) and a solvent-assisted grafting technique to successfully fabricate a free-standing polymeric film. Within the polymeric film the silver nanoparticles have been embedded in chain-like arrays.

The preparation of ordered nanoparticle arrays leads to a number of potential applications in optics, electronics, sensors and so on. In addition, fabricating these ordered nanoparticle arrays (by embedding them) into transparent or flexible polymeric films opens up many avenues towards miniaturized plastic optoelectronics and light-emitting devices (LEDs).

The optically active flexible polymeric films are made by using a specifically patterned poly(vinylpyridine) (PVP) monolayer (polymer brush) which is deposited on a flat substrate and is then used as a 'master' to guide the silver nanoparticles assembly. Once the ordered layer of nanoparticles are transferred to the polymer film, the 'master' can be reused to fabricate the next film. This method therefore leads towards possible mass production of this optically active polymeric film.

Their resulting film is free-standing, transparent, mechanically robust, flexible and exhibits polarization-sensitive optical properties. 

There are two major directions for future development of this work. 'One is focusing on the technical improvements of the production methodology in order to achieve better properties, reproducibility and lower production costs. The second direction is the development of optical components with different properties' said Luzinov.

Emma Shiells