pH-sensitive behavior of the PS-b-PDMAEMA copolymer at the air - water interface

POLYMER

卷:221

Article

Bondaz, Louis^1,2,3,4  Cousin, Fabrice⁵  Muller, Francois^2,3,5  Pantoustier, Nadege⁶  Perrin, Patrick⁶  Luchini, Alessandra^7,9  Goldmann, Michel^1,4,8  Fontaine, Philippe^1,4 

[1] Synchrotron SOLEIL, BP 48, F-91192 Gif Sur Yvette, France

[2] ECE Paris Ecole Ingenieurs, Nanosci & Nanotechnol Grp, F-75015 Paris, France

[3] INSEEC U Res Ctr, F-75015 Paris, France

[4] UPMC Univ Paris 06, Sorbonne Univ, CNRS, UMR 7588,Inst NanoSci Paris, 4 Pl Jussieu, F-75005 Paris, France

[5] Univ Paris Saclay, CNRS, CEA, CEA Saclay,Lab Leon Brillouin, F-91191 Gif Sur Yvette, France

[6] Sorbonne Univ, PSL Univ, CNRS, ESPCI Paris,Soft Matter Sci & Engn, F-75005 Paris, France

[7] Inst Laue Langevin, 71 Ave Martyrs,CS 20156, F-38042 Grenoble 9, France

[8] Univ Paris, Fac Sci Fondament & Biomed, 45 Rue St Peres, F-75006 Paris, France

[9] Univ Copenhagen, Niels Bohr Inst, Univ Pk 5, DK-2100 Copenhagen, Denmark

关键词: Amphiphilic diblock copolymers;    Polyelectrolytes;    Neutron reflectivity;    Polymer at the air/water interface;    Polyelectrolyte brush;    Scaling laws;   

DOI  :  10.1016/j.polymer.2021.123619

来源: Elsevier

【 摘 要 】

We investigated the behavior of a pH-responsive polystyrene-b-poly(2-dimethylamino)ethyl methacrylate (PS-b-PDMAEMA) diblock copolymer at the air/water interface. We synthetized different copolymers with a small hydrophobic PS block of constant length attached to polyelectrolyte PDMAEMA blocks of various lengths. We demonstrate that a Langmuir monolayer is formed with the hydrophobic collapsed PS block anchoring the hydrophilic polyelectrolyte at the interface. By combining macroscopic surface pressure measurements and specular neutron reflectivity, we studied the monolayers as a function of surface density sigma and pH of the subphase. At pH = 2, the PDMAEMA is fully charged and the system at high s behaves as a polyelectrolyte brush with chains protruding in water with a gaussian profile. At pH = 10 where the PDMAEMA is neutral, the system exhibits a phase transition between the pancake configuration to the brush configuration, with a threshold that depends on the PDMAEMA chain length, in agreement with theoretical predicted scaling laws.

【 授权许可】

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