Poroviscoelasticity and compression-softening of agarose hydrogels

Abstract

Agarose hydrogels are poroviscoelastic materials that exhibit a waterlogged crosslinked microstructure.

Spontaneous Formation of Microgels for a 3D Printing Supporting Medium

“…It is known that as the agar concentration is increased, the network structure of the hydrogel becomes denser. That is, the mean pore diameter of the random fibrillar network is found to be smaller upon increasing the agar concentration according to cryo-SEM micrographs. , Therefore, the fibrillar network of the fluid gel (1 wt %) is expected to have a denser structure (smaller mean pore size) than that of self-forming microgels (0.3 wt %). In other words, the gelled particle of the former (higher density) is smaller than that of the latter.…”

“…However, the 1 wt % highly jammed dispersion remains static at the bottom of the inverted vial and does not flow downward at all. In the test of a falling steel ball with a diameter of 2.5 mm and a density of 7.7 g/cm 3 , the ball settles down to the bottoms of tubes containing the first three dispersions but remains sitting at the interface of the highly jammed dispersion shown in Figure 4b, indicating that the yield stress of the latter is able to impede the sedimentation of the ball. The above findings reveal that the mechanical strength of the highly jammed dispersion is strongest among these yield stress fluids.…”

“…Agarose is linear and neutral and made up of the repeating unit agarobiose disaccharide, while agaropectin is a sulfated galactan mixture. The former is able to gel in water, but the latter is not. , Because of the thermoreversible gelling property, agar is widely utilized in many industries as an absorbent, emulsifier, thickener, and gelling agent. − It can dissolve in hot water as the temperature reaches about 85 °C (melting temperature). When the aqueous agar solution is cooled below about 35 °C (gelling temperature), the gel held together by hydrogen bonds begins to develop.…”

“…The former is able to gel in water, but the latter is not. 3,4 Because of the thermoreversible gelling property, agar is widely utilized in many industries as an absorbent, emulsifier, thickener, and gelling agent. 5−7 It can dissolve in hot water as the temperature reaches about 85 °C (melting temperature).…”

Poroviscoelasto-plasticity of agarose-based hydrogels

“…The behavior of agarose gels, and many other biopolymers, is considered to be poroviscoelastic because of their high-water content. [18][19][20] Fluid movement and mass transport through the solid network influence behavior. However, existing poroviscoelastic models fail to connect the network topology with the mechanical response of the solid phase within hydrogels.…”