Microstructure-driven self-assembly and rheological properties of multi-responsive soft microgel suspensions

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:581

Article

Dieuzy, Eva^1,2,3  Aguirre, Garbine^1,3  Auguste, Stephane^3,4  Chougrani, Kamel⁵  Alard, Valerie⁵  Billon, Laurent^1,2,3  Derail, Christophe^1,2 

[1] Univ Pau & Pays Adour, Inst Sci Analyt & PhysicoChim Environm & Mat, E2S UPPA, CNRS,UMR5254, F-64000 Pau, France

[2] LERAM, LabCom UPPA URGO, Helioparc,2 Ave Angot, F-64053 Pau, France

[3] E2S UPPA, Bioinspired Mat Grp Funct & Self Assembly, Helioparc,2 Ave Angot, F-64053 Pau, France

[4] URGO RECH INNOVAT & DEV, 42 Rue Longv, F-21300 Chenove, France

[5] LVMH Rech Parfums & Cosmet, 185 Av Verdun, F-45804 St Jean De Braye, France

关键词: Microgels;    Stimuli-responsive;    Microstructure;    Rheology;    Yield stress;   

DOI  :  10.1016/j.jcis.2020.07.137

来源: Elsevier

【 摘 要 】

Hypotheses: The deformation and swelling ability of microgels is influenced by the crosslinking distribution. Varying microgels microstructure is expected to obtain suspensions with different flow behavior and thereby, different rheological properties. Experiments: Different multi-responsive microgels were synthesized using two different crosslinkers and varying their amounts: N,N-methylene bis-acrylamide (MBA) and oligo(ethylene glycol) diacrylate (OEGDA). The rheological results were obtained by zero-shear viscosity and long-time creep measurements on concentrated microgel suspensions Microgel microstructure was analyzed by 1(H) nuclear magnetic resonance transverse relaxation measurements. Findings: At a constant crosslinking rate, we show that the viscosity of OEGDA-crosslinked microgels diverges at a higher concentration than MBA ones, suggesting a looser shell and less restricted dangling chains at the periphery for the later. By scaling with the effective volume fraction, the viscosity curves of the different microgel suspensions reduce into a single curve and closely follow hard sphere models up to phi(eff) < 0.45. The results from creep tests revealed a much higher yield stress for MBA-crosslinked microgels, strengthening the hypothesis of a looser shell for the later. Finally, transverse relaxation (T-2) NMR measurements demonstrated that, although all microgels exhibit a core-shell microstructure, MBA samples present a less crosslinked shell corroborating with the rheological results. (C) 2020 Elsevier Inc. All rights reserved.

【 授权许可】

Free