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Bio-inspired Photonics

 

Hydroxypropyl Cellulose Self-Assembly

In nature, cellulose and similar polysaccharides form complex nanostructures that confer vivid colours to organisms. However, efforts to develop functional materials from cellulose have been frustrated by the insolubility of cellulose in water.  Hydroxypropyl cellulose (HPC) is a soluble ether derivative of cellulose that can form self-assembled structures similar to those of cellulose in water and many common solvent systems. Furthermore, hydroxylpropyl cellulose is biocompatible, edible and as such, commonly found as a thickening agent in pharmaceuticals and food products.

 

At a high concentration, hydroxypropyl cellulose self-assembles into a lyotropic polymer liquid crystal with chiral nematic order. The pitch of its helical structure can be adjusted to reflect visible light and appear iridescent, as seen in the photographs above. Given the low cost of HPC and its ease of manipulation, many commercial applications, such as large area sensing devices, can be envisioned. A large range of colour can be obtained by varying the concentration of HPC, but that can pose a problem for further development as the colour of dry HPC lies in the UV. In this lab, we focus on understanding the self-assembly of HPC through optical measurements as well as designing approaches towards a visibly coloured sold-state HPC material. 

Related Publications 

Biocompatible and Sustainable Optical Strain Sensors for Large-Area Applications
G Kamita, B Frka-Petesic, A Allard, M Dargaud, K King, AG Dumanli, S Vignolini – Advanced Optical Materials (2016) 4, 1950