Interplay of Thermosensitivity and pH Sensitivity of Amphiphilic Block–Gradient Copolymers of Dimethylaminoethyl Acrylate and Styrene

Mariia Rabyk (1) , Aurélie Destephen (2) , Alain Lapp (3) , Stephen King (4) , Laurence Noirez (3) , Laurent Billon (2) , Martin Hruby (1) , Oleg V. Borisov (2) , Petr Stepanek (1) , Elise Deniau-Lejeune (2)

1 IMC / CAS - Institute of Macromolecular Chemistry of the Czech Academy of Sciences
2 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
3 LLB - UMR 12 - Laboratoire Léon Brillouin
4 ISIS - ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ISIS Neutron and Muon Source

ovel pH- and thermoresponsive amphiphilic diblock copolymer, comprising hydrophilic poly(2-dimethylaminoethyl acrylate) (PDMAEA) and amphiphilic poly(styrene-grad-2-dimethylaminoethyl acrylate) (P(S-grad-DMAEA)) blocks, was synthesized by nitroxide-mediated radical polymerization. A series of copolymers (PS-grad-PDMAEA) with controlled molar masses and low dispersities over a wide range of monomer feed ratios (0 < fS,0 < 1) were synthesized. Both conventional linearization and nonlinear least-squares methods were applied to estimate reliable values of the reactivity ratios for S and DMAEA radical polymerization. The calculated values of the reactivity ratios (rDMAEA = 0.25 and rS = 1.15) perfectly fitted the drift in monomer feed ratio versus conversion, showing a gradient distribution along the copolymer chains. The self-assembling behavior of the copolymers in the aqueous medium was investigated by dynamic light scattering and small-angle neutron scattering over a wide range of pH, temperature, and salt concentration. These block-gradient copolymers show reversible self-association into micelle-like structure (Dh ∼ 20 nm) in aqueous solutions triggered by both pH and temperature

Mots clés: Thermosensitivities; Amphiphilic diblock copolymers; Controlled molar mass; Gradient copolymers; Gradient distributions; Micelle-like structures; Nitroxide mediated radical polymerization; Nonlinear least squares methods

Domaines: Chimie théorique et/ou physique; Chimie analytique; Polymères; Matériaux

Mariia Rabyk, Aurélie Destephen, Alain Lapp, Stephen King, Laurence Noirez, et al.. Interplay of Thermosensitivity and pH Sensitivity of Amphiphilic Block–Gradient Copolymers of Dimethylaminoethyl Acrylate and Styrene. Macromolecules, 2018, 51 (14), pp.5219 - 5233. ⟨10.1021/acs.macromol.8b00621⟩. ⟨hal-01860230⟩