Electrowetting on Paper for Electronic Paper Display

The use of paper as a material for various device applications (such as microfluidics and energy storage) is very attractive given its flexibility, versatility and low cost. Here we demonstrate that electrowetting (EW) devices can be readily fabricated on paper substrates. Several categories of paper have been investigated for this purpose, with the surface coating roughness, thickness, and water uptake among the most important properties. The critical parameter for EW devices is the water contact angle (CA) change with applied voltage. EW devices on paper exhibit characteristics very close to those of conventional EW devices on glass substrates. This includes a large CA change in oil ambient (90-95%), negligible hysteresis (similar to 2 degrees), and fast switching times of similar to 20 ms. These results indicate the promise of low-cost paper based EW devices for video rate flexible e-paper on paper.