Fig. 2: Rheology of fumed silica/DES mixtures.
From: Sensorized tissue analogues enabled by a 3D-printed conductive organogel
Different surface capping groups are present on Aerosil R711 (3-trimethoxysilylmethacrylate-capped), R974 (methyl-capped), and 200 (hydroxyl-capped) fumed silica particles, respectively (a–c). Viscosity measurements (d) and the inversion test (d, inset) revealed that the mixture formed a shear-thinning gel when 12 wt.% of the trimethoxysilylmethacrylate-coated fumed silica (R711) was added to the PEG-based deep-eutectic solvent. An oscillatory amplitude sweep (e) performed on this mixture further indicated gel formation. In contrast, mixtures that used methyl-capped fumed silica (R974) consisted of shear-thickening fluids (f) when silica concentration was increased to 12 wt.%. A picture of the shear-thickening fluid with 12 wt.% R974 is shown in the inset of f. Mixtures that used hydroxyl-capped fumed silica (Aerosil 200) consisted of shear-thinning fluids at 4 wt.% and shear-thickening fluids at 8 and 12 wt.% (g). A picture of the shear-thickening fluid with 12 wt.% Aerosil 200 is shown in the inset of g.
