Deformable coloring element using an electroactive hydrogel with bottom-arranged electrodes

By using an electroactive hydrogel piece and bottom-arranged electrodes. By using the bottom arrangement of electrodes, we can use a simple fabrication and achieve a high fill factor (FF). To design the element, we analyzed the electric field in various dimensions of the electrodes by using a charge simulation method. The bending factor (BF) was defined as an index of bending direction and speed of the gel. From the difference between the BFs for each dimension, we found the optimal parameters required to maximize BF on the chosen boundary condition of FF ≥ 0.9. We then determined the dimensions of a coloring element on the basis of the results of the analysis. Finally, a 3 × 3 dot-matrix display was fabricated to demonstrate a color change in all nine cells.