Microgel structure-driven linear and non-linear mechanical properties of self-assembled microgel films

Éva Dieuzy , Stéphane Auguste , Kamel Chougrani , Valérie Alard , Laurent Billon (1) , Christophe Derail (1)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

Soft self-supported cohesive films were formed by self-assembly of pH- and thermo-responsive P(MEO2MA-co-OEGMA-co-MAA) microgels without any preparation and/or post-treatments. Linear and non-linear mechanical properties of those films were characterized respectively by dynamic mechanical measurements at low strain and uniaxial extensional tests at high deformation. A relationship between the microstructure of microgels and the mechanical strength of microgel-based films was successfully established. Compared to microgels crosslinked with Oligo(ethylene glycol) diacrylate (OEGDA), microgels with N,N-methylenebisacrylamide (MBA) demonstrate a less crosslinked structure but especially a looser shell which enables the particles to better interpenetrate between one another and resist to higher deformation. Novel films were also designed by controlled mixing microgels and the synthesis side-product, namely water-soluble polymer, WSP, in a ratio with WSP content till 100 %. Those films demonstrated promising mechanical properties due to the structural characteristics of the later. The later act as a lever to tune the elastic modulus of films without diminishing their resistance at strain thanks to its high molar mass and crosslinked structure revealed by Steric Exclusion Chromatography (SEC) measurements.

Mots clés: Microgels; Particle-based films; Dynamic mechanical measurements; Linear; Non-linear; Structure-Properties relationship

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

Éva Dieuzy, Stéphane Auguste, Kamel Chougrani, Valérie Alard, Laurent Billon, et al.. Microgel structure-driven linear and non-linear mechanical properties of self-assembled microgel films. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2021, 613, pp.126082. ⟨10.1016/j.colsurfa.2020.126082⟩. ⟨hal-03126992⟩