Development of Visible Light Responsive Double Polyacrylamide-poly(acrylic acid) Network Hydrogels for Tactile Display

The purpose of this project is to investigate the swelling ratio exhibited due to photothermal effects of double network polyacrylamide poly(acrylic acid) hydrogels synthesized with carbon black as a light-sensitive chromophore. Optimal carbon black dispersion was achieved in solutions through sonication, using V9A32 carbon black, where dynamic light scattering recorded particle diameters in the range of 195.0-375.8 nanometers for water/carbon black mixtures, 242.4-262.6 nanometers for monomer/carbon black mixtures without initiator, and 1109.3-1783.9 nanometers for monomer/carbon black mixtures including initiator. The double network polyacrylamide poly(acrylic acid) hydrogels with carbon black yielded weight increases of 0.126% and 6.043%, respectively, after 2 minutes and 10 minutes of being exposed to a light stimulus; compared to previous work which showed a double network polyacrylamide poly(acrylic acid) hydrogel with chlorophyllin yielded weight increases of 18.3% and 20.8%, respectively, after 2 minutes and 10 minutes of being exposed to a light stimulus, the carbon black resulted in a less robust response. Future work for application of the light-responsive hydrogels includes the development of a screen covering that will be made of the hydrogels. This covering is intended for use on LED screen displays, where a light change will result in a protrusion from the screen. The purpose behind this application is that technology users who are visually impaired can still determine what their LED device is trying to communicate with them.