Poly(allylamine)-graft-poly(N-isopropylacrylamide)/Poly(styrene sulfonate) Sodium Salt Multilayers: Buildup, Wettability, and Mechanical Properties

✍ Scribed by Feng Wang; Linhui Li; Changyou Gao

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 401 KB
• Volume: 210
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200900304

✦ Synopsis

Abstract

Poly(allylamine)‐graft‐poly(N‐isopropylacrylamide) (PAH‐g‐PNIPAAm)/poly(styrene sulfonate) sodium salt (PSS) multilayer films are prepared using electrostatic layer‐by‐layer assembly. Buildup of the PAH/PSS and PAH‐g‐PNIPAAm/PSS multilayers under different salt concentrations and different temperatures is compared by using ellipsometry and scanning force microscopy. All the film thicknesses increase linearly with the increase of layer number regardless of their assembly conditions. However, the average layer thickness of the PAH‐g‐PNIPAAm/PSS multilayers is larger than that of the PAH/PSS multilayers under the same assembling conditions. Their surfaces also become rougher and show higher water contact angles. In contrast to the apparent loss transition in the friction force curve of the PAH/PSS multilayers, the PAH‐g‐PNIPAAm/PSS multilayers with PAH‐g‐PNIPAAm as the outmost layer do not undergo a pressure‐induced glass transition in water. Nanoindentation tests show that the elastic modulus of the PAH‐g‐PNIPAAm/PSS multilayers is only 75% of that of the PAH/PSS multilayers.

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