Plastic Bags and the DNA in our cells are both polymers, very long molecules ubiquitous in nature and in their synthetic form, in materials like polythene, perspex and polystyrene. Professor Dame Julia Higgins has spent a lifetime researching the structure and movement of polymeric material. Trained as a physicist, Dame Julia was one of the early researchers in polymer science and throughout her career worked alongside chemists and engineers. No surprise then that she was the first woman to become both a Fellow of the Royal Society and of the Royal Academy of Engineering. In the 1960s with other young researchers she worked at the Harwell Atomic Energy Research Centre in Oxfordshire, one of the first people to use neutron scattering as a technique to investigate how polymer molecules move. Emeritus Professor of Polymer Science and former Principal at the Faculty of Engineering at Imperial College, London, Professor Higgins tells Jim Al-Khalili how she used her influence as a leading academic to improve representation of women in top posts in science and medicine.