Designing superoleophobic surfaces with fluorinated polyhedral oligomeric silsesquioxanes

POLY 580

Anish Tuteja, atuteja@mit.edu1, Wonjae Choi2, Joseph M. Mabry, joseph.mabry@edwards.af.mil3, Gareth H. McKinley4, and Robert E. Cohen1. (1) Department of Chemical Engineering, Massachusetts Institute of Technology, Bldg. NE-47, Room 583, 500 Technology Square, Cambridge, MA 02139, (2) Department of Mechanical Engineering, Massachusetts Institute of Technology, MA, (3) AFRL/RZSM, Air Force Research Laboratory, 10 East Saturn Boulevard, Edwards AFB, CA 93524, (4) Hatsopoulos Microfluids Laboratory, Department of Mechanical Engineering, Massachusetts Institute of Technology, MA
Superhydrophobic surfaces display water contact angles greater than 150 in conjunction with low contact angle hysteresis. Microscopic pockets of air trapped beneath the water droplets placed on these surfaces lead to a composite solid-liquid-air interface in thermodynamic equilibrium. Previous experimental and theoretical studies suggest that it may not be possible to form similar fully-equilibrated, composite interfaces with drops of liquids such as alkanes or alcohols that possess significantly lower surface tension than water. In this work we develop surfaces that can support strongly metastable composite solid-liquid-air interfaces even with very low surface tension liquids such as pentane. In this work, we produce two different families of re-entrant surfaces randomly-deposited electrospun fiber mats and precisely fabricated micro-hoodoo surfaces that can each support a robust composite interface with essentially any liquid. These omniphobic surfaces display contact angles greater than 150 and low contact angle hysteresis with both polar and non-polar liquids possessing a wide range of surface tensions.