Adsorption dynamics of hydrophobically modified polymers at an air-water interface

C. Trégouët; A. Mikhailovskaya; T. Salez; N. Pantoustier; P. Perrin; M. Reyssat; C. Monteux

doi:10.1140/epje/i2018-11711-y

2022 Impact factor 1.8

Soft Matter and Biological Physics

Polymers: From Adsorption to Translocation - Topical Issue in Memoriam Loïc Auvray (1956-2016)

Eur. Phys. J. E (2018) 41: 101
https://doi.org/10.1140/epje/i2018-11711-y

Regular Article

Adsorption dynamics of hydrophobically modified polymers at an air-water interface

C. Trégouët¹^,2, A. Mikhailovskaya¹, T. Salez³^,4, N. Pantoustier¹, P. Perrin¹, M. Reyssat²^* and C. Monteux¹^,4^*

¹ Laboratoire Sciences et Ingénierie de la Matière Molle, PSL Research University, UPMC Univ Paris 06, ESPCI Paris, UMR 7615 CNRS, 10 rue Vauquelin, 75231, Paris Cedex 05, France
² UMR CNRS Gulliver 7083, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75231, Paris cedex 05, France
³ Univ. Bordeaux, CNRS, LOMA, UMR 5798, F-33405, Talence, France
⁴ Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, 060-0808, Hokkaido, Japan

^* e-mail: mathilde.reyssat@espci.fr
^** e-mail: cecile.monteux@espci.fr

Received: 16 February 2018
Accepted: 1 August 2018
Published online: 6 September 2018

Abstract

Using surface-tension measurements, we study the brush-limited adsorption dynamics of a range of amphiphilic polymers, PAAH-- composed of a poly(acrylic acid) backbone, PAAH, grafted with a fraction of alkyl moieties, containing either n = 8 or n = 12 carbon atoms, at pH conditions where the PAAH backbone is not charged. At short times, the surface tension decreases more sharply as the degree of grafting increases, while, at long times, the adsorption dynamics becomes logarithmic in time and is slower as the degree of grafting increases. This logarithmic behavior at long times indicates the building of a free-energy barrier which grows over time. To account for the observed surface tension evolution with the degree of grafting we propose a scenario, where the free-energy barrier results from both the deformation of the incoming polymer coils and the deformation of the adsorbed brush. Our model involves only two fitting parameters, the monomer size and the area needed for one molecule during adsorption and is in agreement with the experimental data. We obtain a reasonable value for the monomer size and find an area per adsorbed polymer chain of the order of 1 nm², showing that the polymer chains are strongly stretched as they adsorb.