Figure 3.

Bridging the gap. (a) Stress–elongation comparison of Group 1 (n_sc = 14, dashed) versus Group 2 (n_sc = 70, solid) plastomers with similar B-block backbone DP n_bb = 300 and L-block volume fraction ϕ_L = 0.3–0.9 demonstrate Group 2’s enhanced strain-stiffening. (b) The E₀ vs β plot from Figure 1d where Group 1 plastomers (green) enable gel-tissue bridging, while Group 2 plastomers (black) successfully penetrate into the tissue territory (Tables S1–S3). Dashed lines are used to guide the reader and not indicative of theoretical correlation. Group 2 plastomers with shorter backbones (n_bb = 100) shift toward higher E₀ (black ●), due to a star-like strand conformation as n_bb ≈ n_sc (Figure S1). (c) Correlation between mechanical properties (E₀ and β) and molecular parameters (n_L, n_bb, ϕ_L) demonstrate good agreement with theoretical analysis summarized in eq S10, where ϕ=n_g/(n_g+n_sc). (d) Selected USAXS/SAXS spectra of Group 1 and 2 plastomers with a similar n_bb ≅ 300 (see Supporting Information for a complete set of X-ray curves for a complete set of X-ray curves). The observed increase of the interdomain spacing (d₃) of Group 2 plastomers correlates with enhanced strain-stiffening from longer side chains. (e) Uniaxial extension of a Group 1 plastomer results in a d₃ increase obtained from in situ variation of the structure factor S(q) in the stretching direction (arrow in inset). S(q) was computed by dividing the total scattering intensity by the fit of the form-factor of polydisperse solid spheres. The 2D USAXS patterns given in the inset correspond the to the values of λ of 1.0, 1.4, and 2.0 (from left to right). Azimuthal variations in the 2D USAXS pattern suggest network topology restructuring during deformation. (f) Relative decrease of the d₁ spacing during elongation was deduced from the high-q shifts of the bottlebrush peak (insets) with Group 2 plastomers exhibiting stronger dependence consistent with enhanced strand firmness.