Synergy, competition, and the hanging polymer layer: Interactions between a neutral amphiphilic 'tardigrade' comb co-polymer with an anionic surfactant at the air-water interface

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:561

Article

Slastanova, Anna¹  Campbell, Richard A.^2,7  Snow, Tim^1,3  Mould, Elizabeth^1,8  Li, Peixun⁴  Welbourn, Rebecca J. L.⁴  Chen, Meng⁵  Robles, Eric⁶  Briscoe, Wuge H.¹ 

[1] Univ Bristol, Sch Chem, Bristol BS8 1TS, Avon, England

[2] Inst Laue Langevin, 71 Ave Martyrs,CS20156, F-38042 Grenoble, France

[3] Diamond Light Source Ltd, Diamond House,Harwell Sci & Innovat Campus, Didcot OX11 0DE, DE, England

[4] Rutherford Appleton Lab, STFC, ISIS Facil, Didcot OX11 0QX, Oxon, England

[5] Procter & Gamble Beijing Innovat Ctr, 35 Yuan Rd, Beijing 101312, Peoples R China

[6] Procter & Gamble Newcastle Innovat Ctr, Household Care Analyt, Whitley Rd, Longbenton NE12 9TS, Newcastle, England

[7] Univ Manchester, Div Pharm & Optometry, Manchester M13 9PT, Lancs, England

[8] Infineum UK Ltd, POB 1,Milton Hill, Abingdon OX13 6BB, Oxon, England

关键词: Polymer/surfactant interactions;    Air-water interface;    Synergy;    Competition;    Foaming;    Comb co-polymer;    Neutron reflectivity;   

DOI  :  10.1016/j.jcis.2019.11.017

来源: Elsevier

【 摘 要 】

Understanding the structure of polymer/surfactant mixtures at the air-water interface is of fundamental importance and also of relevance to a variety of practical applications. Here, the complexation between a neutral 'tardigrade' comb co-polymer (consisting of a hydrophilic polyethylene glycol backbone with hydrophobic polyvinyl acetate grafts, PEG-g-PVAc) with an anionic surfactant (sodium dodecyl sulfate, SDS) at the air-water interface has been studied. Contrast-matched neutron reflectivity complemented by surface tension measurements allowed elucidation of the interfacial composition and structure of these mixed systems, as well as providing physical insights into the polymer/surfactant interactions at the air-water interface. For both polymer concentrations studied, below and above its critical aggregation concentration, cac, (0.2 cac and 2 cac, corresponding to 0.0002 wt% or 0.013 mM and 0.002 wt% or 0.13 mM respectively), we observed a synergistic cooperative behaviour at low surfactant concentrations with a 1-2 nm mixed interfacial layer; a competitive adsorption behaviour at higher surfactant concentrations was observed where the polymer was depleted from the air-water interface, with an overall interfacial layer thickness similar to 1.6 nm independent of the polymer concentration. The weakly associated polymer layer hanging proximally to the interface, however, played a role in enhancing foam stability, thus was relevant to the detergency efficacy in such polymer/surfactant mixtures in industrial formulations. (C) 2019 Elsevier Inc. All rights reserved.

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