Abstract
The re-entrant phase separation inside an evaporating droplet of poly (N-isopropyl acryl amide) (PNIPAM) solution with the binary solvent of ethanol and water is discovered and monitored continuously by optical microscopy. Because of the higher evaporation rate of ethanol than water, the solvent composition is changed by evaporation. As a result, the cononsolvency of PNIPAM makes the polymer precipitate into the solution and redissolve afterwards along the proceeding of the evaporation. Such a simple strategy enables a continuous observation of the re-entrant phase separation due to cononsolvency. Direct optical microscopic observation is made with quantitative description of the process and the details of the flow patterns during the process. The phase separation is found to occur at the air-liquid interface and the precipitates are brought into the droplet by circulations induced by Marangoni flow, providing a new way of mass transportation during phase separation.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
