Sequential Folding using Light-activated Polystyrene Sheet

A pre-strained polystyrene (PS) polymer sheet is deformed when it approaches the glass transition state as a result of light absorption. By controlling the light absorption of the polymer sheet, non-contact sequential folding can be accomplished. Line patterns of different transparencies and shapes are used to control the light absorption. The line pattern shape is closely related to the folding angle and folding start time. The relation between the line pattern design and folding performance was evaluated experimentally to develop a technique for folding PS sheets. The results show that sequential folding of PS sheets can be accomplished by changing the degree of transparency of the line pattern. Using the technique developed in this study, self-folding origami structures with complicated shapes can be designed and manufactured.