03 June 2010
In living nanocolour
RMPC researchers, Dr Sumanta Raha and Professor Sati Bhattacharya. Photo: Carla Gottgens.
Imagine a world where paint doesn’t fade. Research into nanopigment technology could soon make colour fading in paint, plastics, textiles, glass and ceramics a thing of the past. And it will be non-toxic and environmentally friendly.
Professor Sati Bhattacharya and his team at RMIT’s Rheology and Materials Processing Centre (RMPC) have started the patenting process for the technology that provides better colour-fastness and also resists colour fading.
Their nanopigments use coloured particles that range in size from 50 to 100 nanometres. A nanometre is one-millionth of a millimetre, or one-billionth of a metre. They can be seen only under a powerful microscope, and help to evenly distribute colour across the surface of materials.
"Nanopigments can provide much better stability against fading and colour fastness for paints," Bhattacharya says. "They maintain their fluorescence and colour stability after exposure to sunlight, while ordinary dyes fade.
"They also replace the hazardous heavy metal-based pigments that are currently used. The nanopigments use an organic base, without the toxic components such as cadmium, copper and other metals that we usually find."
Bhattacharya’s team worked on a two-year project with Nanotechnology Victoria and Allied Colors and Additives before starting their patent application last November.
Responding to industry needs, their focus was on fluorescent nanopigments, resulting in intellectual property development, protection and a licensing agreement with Aron Universal Ltd, which describes itself as India’s largest manufacturer and exporter of daylight fluorescent colours.
"Our design process means if we want a fluorescent pigment with a certain colour, we produce the nanopigment of the colour we want. It allows us to customise the nanopigments, so eventually you can have a greater variety of colours," Bhattacharya says.
He and his team are also looking for ways to develop cool, black paints that reflect heat - particularly useful in a world where black cars of all shapes and sizes are becoming increasingly popular.
This work is currently concentrating on heat-reflecting pigments for car paint that can help to better protect vehicles from the effects of sun exposure. Originally part of a project researching cool pigments for the automotive industry, their work is not just concentrating on the outside of the car.
Supported by the Cooperative Research Centre for Advanced Automotive Technology (AutoCRC), and Holden GM, the RMPC is looking at how such pigments can be used on the plastics and other compounds used in car interiors as well.
By reducing the car’s absorption of heat, its internal temperature can be reduced, leading to improved comfort and reducing the use of air-conditioning, thereby saving energy consumption.
"The main challenge in achieving the effect of heat reflection is the need for maintaining the desired colour, such as black, which would normally absorb most heat," Bhattacharya says.
"The idea is that we are looking into the structure of these chemicals and how we can change those structures that will give us better heat reflection."
Bhattacharya’s team members for nanopigment research are Dr Ivan Ivanov, Dr Sumanta Raha and Dr Nurul Quazi and PhD candidates, Edwin Baez and Balwinder Kaur.