The University of Sheffield’s researchers have manufactured pigment-free polymers that could be used to fight against counterfeiting on passports and banknotes. The newly developed polymers produce intense colours, which have been created using polymer layers. The scientists created a range of colours by mixing two different block copolymers in varying proportions.
The polymer materials can be made into robust layers that could be used as anti-counterfeit measures on banknotes.
The polymer material arranges automatically into a layered structure, producing optical effects that are similar to opal stones. The intense colour also gets altered based on the viewing angle. This technique provides better colour selection, processing and cost benefits than existing anti-counterfeit systems. The complexity of the polymer formulation makes it difficult for counterfeiters to copy.
The University of Sheffield used the national synchrotron science facility in Oxfordshire, UK to analyze the layered structures of polymer using small angle X-ray techniques. The analysis helps understand the formation of colours and ways to enhance the appearance.
With the use of high power X-rays in the Diamond Light Source laboratory, the researchers were able to discover the optimal blends of colours and can modify the polymer composition as required.