US 11,840,609 B1
Method to prepare superhydrophobic sheets from virgin and waste polypropylene
Junaid Saleem, Al-Ahsa (SA); Safdar Hossain Sk, Al-Ahsa (SA); Zubair Khalid Baig Moghal, Al-Ahsa (SA); and Gordon McKay, Al-Ahsa (SA)
Assigned to KING FAISAL UNIVERSITY, Al-Ahsa (SA)
Filed by KING FAISAL UNIVERSITY, Al-Ahsa (SA)
Filed on Apr. 12, 2023, as Appl. No. 18/133,983.
This patent is subject to a terminal disclaimer.
Int. Cl. C08J 11/08 (2006.01); C08J 7/04 (2020.01); B05D 3/02 (2006.01); B05D 7/00 (2006.01)
CPC C08J 11/08 (2013.01) [B05D 3/0218 (2013.01); B05D 7/5383 (2013.01); C08J 7/042 (2013.01); B05D 2203/35 (2013.01); B05D 2252/00 (2013.01); B05D 2401/10 (2013.01); B05D 2507/02 (2013.01); C08J 2323/12 (2013.01)] 14 Claims
 
1. A method of making a superhydrophobic sheet, the method comprising:
dissolving polypropylene (PP) isolated from plastic waste in a solvent to form a clear polypropylene solution;
pre-heating a solid substrate to a temperature below a boiling point of the solvent;
applying a portion of the clear polypropylene solution onto the solid substrate and drying the solvent from the polypropylene solution using vacuum or air to obtain a porous base layer
annealing the porous base layer at a temperature above the melting point of polypropylene for a specific period of time to obtain a non-porous base layer;
applying a top layer comprising a heated portion of the clear polypropylene solution on the non-porous base layer while the non-porous base layer is hot;
drying the solvent from the clear polypropylene solution forming the top layer using vacuum or air to provide a top layer having a contact angle ranging from 140 degrees to 160 degrees; and
separating the top and base layers of polypropylene from the substrate to obtain a superhydrophobic sheet having a thickness ranging from about 10 μm to about 200 μm and a tensile strength ranging from about 5 MPa to about 70 MPa.