Fig. 1 (Sketch not to scale) ( a ) A strained nanostructured layer of material A and thickness h L is embedded in an infinite-size matrix of material B. A nanowire of material A, width 2 h x and height h y , is considered at the upper layer–matrix interface. The misfit strain between ... More

Fig. 2 Dimensionless force F ~ G + versus the dislocation position x ~ d for different values of the dipole vertical position, with h ~ y = 0.4 and K ~ m = 1 : ( a ) in the upper part of the nanostructure ( y ~ d ... More

Fig. 3 Different regions in the ( h ~ y , y ~ d ) plane of the nanostructure where the dislocation dipole can reach or not equilibrium positions, with K ~ m = 1 More

Fig. 4 Critical misfit parameter ( δa / a eq ) c versus h y / h x for h x = 20 b , 50 b , and 100 b More

Fig. 1 A schematic view of ( a ) the microprobe insertion mechanism into the brain, ( b ) the applied force by the inserter and its effect on the microprobe and brain surface, and ( c ) the intracortical polyimide microprobe with piezoelectric-based stiffness control More

Fig. 2 For three modified polyimide microprobes with different diameters of 20 µ m, 30 µ m, and 40 µ m and piezoelectric layers with thickness of 1 µ m: ( a ) the flexural stiffness ratio, E I * , against the piezoelectric layers angle, θ and ( b ) the generated piezoelectric forc... More

Fig. 3 The dimensionless critical buckling force, P * , of the modified polyimide microprobe against the applied voltage for two different angles of 10 deg and 32 deg More

Fig. 4 The dimensionless critical buckling force, P * , of the modified polyimide microprobe with 1 µ m thick piezoelectric layer and θ = 10 deg against the applied voltage for ( a ) diameter of 20 µ m and different lengths of 2 mm, 5 mm, and 8 mm and ( b ) length of 5 mm and different... More

Fig. 5 The dimensionless critical buckling force, P * , of the modified polyimide microprobe with length of 5 mm and diameters of 20 µ m, and different piezoelectric layer thicknesses of 0.5 µ m, 1 µ m, and 1.5 µ m against the applied voltage More

Fig. 6 ( a ) A 3D model of the simulated microprobe and embedded piezoelectric layers and ( b ) the microprobe lateral displacement against the applied compressive force More

Fig. 1 Fracture mechanism of various hydrogels: ( a ) For a homogeneous hydrogel, the polymer chain at the crack front is highly stretched, and the energy stored in the chain dissipates as the chain ruptures, ( b ) for a 2D composite hydrogel, the fiber at the crack front is highly stretched betwe... More

Fig. 2 Fabrication of composite hydrogels: ( a ) PAAm/Na + -alginate hydrogel, ( b ) soaking the PAAm/Na + -alginate hydrogel in solutions of multivalent cations, ( c ) cation-strengthened PAAm/alginate, ( d ) the stiff hydrogel is cut into a fiber network, ( e ) the soft PAAm hydrogel is casted o... More

Fig. 3 Mechanical properties of soft, stiff, and composite hydrogels: ( a ) Images of PAAm hydrogel and stiff hydrogels strengthened by Zr 4+ , Al 3+ , Ba 2+ , and Cu 2+ , ( b ) stress-stretch curves of the soft hydrogel (PAAm) and stiff hydrogels, ( c ) the modulus of cation-strengthened hydrogel... More

Fig. 4 Effect of the fiber width on the toughness of composite hydrogels: ( a ) Schematic of composite hydrogels with wide and narrow fiber, ( b ) and ( c ) stress-stretch curves of unnotched and notched pure shear samples for composite hydrogels with different fiber widths, ( d ) toughness of com... More

Fig. 5 Effect of the fiber spacing on the toughness of composite hydrogels: ( a ) Schematic of samples with wide and narrow fiber spacing, ( b ) stress-stretch curves of notched samples, ( c ) toughness of composite hydrogels with different fiber spacings, ( d ) stress concentration factor of comp... More

Fig. 6 Effect of the shape of fiber network on the toughness of composite hydrogels: ( a ) Schematic of samples with different fiber network shapes, ( b ) and ( c ) stress-stretch curves of unnotched and notched pure shear samples for the composite hydrogels, ( d ) toughness of the composite hydro... More

Fig. 7 Fatigue of composite hydrogels with circular and triangular fiber network shapes: ( a ) Photos of the notched sample with circular fiber network shape after cyclic stretch, ( b ) cyclic stress-stretch curve, ( c ) G – N curve of the composite hydrogel with circular fiber network shape, ( ... More