Interfacial dynamic and dilational rheology of polyelectrolyte/surfactant two-component nanoparticle systems at air–water interface

• Published in: Applied surface science Vol. 316; pp. 147 - 154
• Main Authors: Tong, L.J., Bao, M.T., Li, Y.M., Gong, H.Y.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.10.2014; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Dilational rheological; Exact sciences and technology; Interfacial dynamic; Nanoparticles; Physics; Surface pressure; Nanoparticles; Surface pressure; Dilational rheological; Interfacial dynamic; Water; Rheology; Surfactants
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2014.07.186

•DTAB/PSS mixture can self-assemble nanoparticles in bulk solution.•The nanoparticles can adsorb at the interface forming a nanoparticle monolayer.•The nanoparticles spread at the interface undergo a disassembly process with time.•The nanoparticle monolayer presents peculiar dilational viscoelastic behavior. The interfacial characteristics of nanoparticles and consequent inter-particle interactions at the interface are poorly understood. In this work, the interfacial dynamic and corresponding dilational surface rheology of self-assembled polyelectrolyte/surfactant nanoparticles at the air–water interface are characterized. The nanoparticles are prepared from dodecyltrimethylammonium (DTAB) and poly (sodium 4-styrene-sulfonate) (PSS) by mixing them in aqueous solution. The interfacial dynamic characteristics have been carried out by comparing the surface pressure with the dilational rheological response of these nanoparticles at interface. The results indicate that this type of nanoparticles can adsorb at the interface forming a nanoparticle monolayer, which leads to the surface tension decreased markedly. The dependence of surface pressure on time shows the instability and disassembly process of nanoparticles at the interface. On the basis of these observations, it is proposed that the nanoparticles undergo a dynamic process that interface induced nanoparticles disassembly into DTAB/PSS complexes. The presence of PSS in the subphase can promote the process of nanoparticles disassembly. A transition point in dilational elasticity and viscosity response of the nanoparticles versus oscillation frequency further validate the micro dynamic process of nanoparticles and the formation of polyelectrolyte/surfactant complex monolayer at the interface.