Fig. 4: Crack propagation resistance of R-PVA20, L-PVA20, and LR-PVA20.
From: Mechanically robust eutectogels enabled by precisely engineered crystalline domains
a Schematic illustration of the specimen in trouser tearing test, divided into four distinct regions: Region-A (test clamping area), Region-B (uniform uniaxial tension), Region-C (crack-front region), and Region-D (stabilized tear area). b Optical photographs captured during the trouser tearing process, showing random crack deflection in LR-PVA20 and L-PVA20, while linear crack propagation in R-PVA20. The red lines distinctly illustrated the morphology of fracture surface and its propagation trend. Scale bar: 1 cm. c Trouser tearing curves of R-PVA20, L-PVA20, and LR-PVA20. d Ashby plot comparing the fracture energy and stress of LR-PVA20 eutectogel with other reported anisotropic gels34, nanocomposite gels53,54,55,70,71, double-network gels74,75, phase separation gels59,60,72,76, and homogeneous network gels16,33,77. e Schematic representation of the network structures in R-PVA20, L-PVA20, and LR-PVA20 eutectogels, highlighting the variations in crystalline domain size, distribution, and their effects on crack propagation and stress distribution. The crystalline domains in L-PVA20 and LR-PVA20 act as effective barriers for crack blunting and uniform stress distribution, as indicated by the orange area. In contrast, the lack of sufficient crystalline domains in R-PVA20 results in unhindered crack growth and high localized stress concentration at the crack tip. f Finite element analysis (FEA) illustrating the stress distribution in R-PVA20, L-PVA20, and LR-PVA20 at the onset of crack propagation. The color scale from red to blue indicates the transition from high to low stress concentration.
