Abstract
Polymer brushes are highly responsive materials with application areas in a broad spectrum. Therefore understanding their interfacial behaviour is essential. Under good solvent conditions, drop spreading causes changes in wettability on the brush surface and results in a finite contact angle. This feature was observed by placing a hexadecane drop on a dry hydrophobic poly lauryl methacrylate (PLMA) brush layer. These polymer brushes were synthesized via ARGET-ATRP to obtain high and low grafting densities and different chain lengths. In a closed chamber, that contained an excess of hexadecane, the spreading of the drop on the polymer brushes was followed by an optical microscope. As a result of the complex dynamics between the drop and the substrate, a halo of a few millimetres in width forms around the macroscopic contact line. A numeric model was extended to simulate such a droplet spreading on a swollen brush for understanding the coupled spreading, evaporation, condensation and wicking dynamics. A continuous gradual flux from liquid to brush, liquid to vapor, and brush to vapor can explain the partially wetting of the polymer brushes in this non-equilibrium state. Understanding the spreading dynamics of a droplet on hydrophobic surfaces will be crucial to explaining the mechanism of the halo formation.
Original language | English |
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Publication status | Published - 13 Jun 2022 |
Event | 2nd Bordeaux Polymer Conference, BPC 2022 - Boredeaux, France Duration: 13 Jun 2022 → 16 Jun 2022 Conference number: 2 |
Conference
Conference | 2nd Bordeaux Polymer Conference, BPC 2022 |
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Abbreviated title | BPC 2022 |
Country/Territory | France |
City | Boredeaux |
Period | 13/06/22 → 16/06/22 |