Supporting Information. Experimental details, supplemental figures referred to in the main text obtained with different techniques (PDF). Video of colloidal particles at reference t=0 min, both at high and low magnification Video of colloidal particles in fuel cycle at t=5 min, both at high and low magnification Video of colloidal particles in fuel cycle at t=180 min, both at high and low magnification "This material is available free of charge via the Internet at ."