Fig. 2: Mechanical modulation enabled by shape memory and wet-adhesive effects.
From: Self-contracting, battery-free triboelectric wound healing strip with strong wet adhesion
a Schematic of strain programming and recovery in electrode substrate via thermally induced shape memory effects of B-SMP, with cross-sectional views depicting the adhesive mechanism to wet tissues. b Stress-strain curve of B-SMP at the room temperature. c DMA analysis of B-SMP: the storage modulus (E’), loss modulus (E”), and loss factor (tan δ). d Shape memory cycle test of B-SMP, illustrating the strain (%) and stress (MPa) as a function of temperature. The key phases of the shape memory process (deformation, fixing, unloading, and recovery) are annotated for clarity. e Quantitative evaluation of adhesion properties of the bioadhesive on wet porcine tissues (left, shear strength; right, interfacial toughness). Data represent mean ± SEM, with dots indicating individual measurements (n = 3 independent samples per tissue type). Statistical significance was assessed using one-way ANOVA (ns, not significant; exact P values are shown). f Quantitative evaluation of adhesion properties on moistened rat skin (shear strength and interfacial toughness), with dots representing individual measurements (n = 3 independent samples per group). g Images of SBF strips on wet tissues: heart, muscle, liver tissues. Scale bar: 1 cm. h Theoretical illustration of stress distribution around a skin wound (σ∞, pre-tension stress in intact skin; σwound, disrupted tensile stress at wound site; σr, radial stress; σθ, hoop stress; μ₀, skin shear modulus), complemented by representative finite-element simulation results.
