Synchronization of Droplet Spreading and Variation of Charge (video) City University of Hong Kong Share Print E-Mail Loading video... Caption The density of surface charges on the PTFE film fluctuates throughout the continuous droplet impinging. Credit City University of Hong Kong / Nature Usage Restrictions The video can only be used with appropriate caption and credit. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.