Memorizing chromic response to pressure

Almost all appliances are prone to mechanical stress in one form or the other. An increasing dependence on machines in daily life calls for a need to increase their maintenance quality. Various materials, methods and configurations to observe mechanical pressure have been devised and this paper discusses one such technique. The use of gold nanoparticles in its one dimensional array causes plasmonic coupling between the nanoparticles, which when disrupted creates a plasmonic shift in its assembly. Such a film, when casted on a polymer with a known elastic limit, causes deformation by an application of stress. This forces the film to undergo plasmonic shift permanently and this is sensed with a change in colour. Because of plastic deformation, the colour remains intact even after the removal of pressure. Analysis of extinction profiles of nanoparticles have been carried out which demonstrates the proof of concept under a wide range of stresses. The colour change depends on the duration of application of stress and the value of stress itself. This is one of the earliest attempts to develop a colorimetric pressure-responsive film which memorizes the colour change by using gold nanoparticles. In this thesis, an attempt is made to investigate the feasibility of using silver nanoparticles in such sensors