Surface hydrophobization by electrostatic deposition of hydrophobically modified poly(acrylates) and their complexes with surfactants

• Published in: Applied surface science Vol. 371; pp. 519 - 529
• Main Authors: Gîfu, Ioana Cătălina, Maxim, Monica Elisabeta, Iovescu, Alina, Simion, Elena Livia, Aricov, Ludmila, Anastasescu, Mihai, Munteanu, Cornel, Anghel, Dan-Florin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-05-2016
• Subjects: Cationic; Chlorides; Deposition; Film roughness; Hydrophobic surface; Hydrophobically modified poly(acrylate); Layer-by-layer deposition; Multilayers; Polyelectrolyte-surfactant complexes; Sodium; Solvents; Surfactants; Water contact angle; Wettability; Water contact angle; Layer-by-layer deposition; Hydrophobically modified poly(acrylate); Film roughness; Polyelectrolyte-surfactant complexes; Hydrophobic surface
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2016.03.036

•Alkyl grafted poly(acrylate)s (PACnNa, n=10,18) are used to obtain hydrophobic films.•PACnNa or its complex with CxTAB (x=10-18) alternate with PDADMAC by LbL technique.•Electrostatic interaction rules the multilayer deposition through a dipping route.•Water drop contact angle increases with the alkyl chains of polymer and surfactant.•SEM and AFM show thinner and respectively, less coarse films by NaCl addition.
The present study demonstrates the hydrophobic effect of poly(electrolyte) multilayer films when they are alkyl-grafted and complexed or not with surfactants. For this purpose, sodium hydrophobically modified poly(acrylates) (PACnNa, n=10, 18) or their anionic complexes with alkyltrimethylammonium bromides (CxTAB, x=10, 12, 14, 18), and the cationic poly(diallyldimethyldiammonium chloride) (PDDAMAC) are assembled by layer-by-layer deposition on a glass substrate. Contact angle (CA) measurements reveal that films constructed with PACnNa-CxTAB/PDADMAC are superior water repellants than those of PACnNa/PDADMAC. For example, the highest CA is obtained for the PAC18Na-C18TAB/PDADMAC. Moreover, it has been observed that the CA increases with the alkyl chain length of PACnNa and of surfactant. The film roughness and thickness have the same trend as wettability. Thinner and less coarse films are obtained by NaCl addition, as witnessed by SEM and AFM.