Materials, Time and Emotion: how materials change in time?

During their lifecycle, objects shift from their initial state of perfection, in which they are conceived by designers and industrial production, and approach an imperfect status. This is shown by changes that impact shape, surface and material properties, due to usage and time. In this paper we focus on the passage of time and its consequences. For some materials ageing is negatively addressed as decaying, for other ones it may have a positive effect to be defined as evolution or maturation. What are the factors that lead to a positive or a negative perception of ageing objects? In other words, what parameters and emotions are ultimately bonded to the idea of evolution or decay? Our main intent is to move the first steps needed to answer these questions to support designers during the phase of material selection. Thanks to an experiment conducted on 25 persons, this paper validates a method to identify the properties subject to time and quantify their variations, which influence the varying user's perception. During the experiment it stood out that materials and their change in time play a crucial role