Fig. 1.

From drops to hairs. (A) Side view comparing the droplets and hairs obtained with VPS-8 at ${\mathrm{\Omega }}_1=400$ rpm, ${\mathrm{\Omega }}_2=\mathrm{1,000}$ rpm, $t^{*}=7$ min. (Scale bar, 3 mm.) (B) Schematic of the experiment coupled with the rheology data of VPS-8 curing in oscillatory shear (strain $5\%$, frequency 0.5 Hz). In step i, a cylinder is initially coated with a liquid elastomer melt undergoing curing. In step ii, while the melt remains liquid ($G^{{}^{″}}\gg G^{\prime }$) the cylinder is rotated at a speed ${\mathrm{\Omega }}_1$ to form an array of droplets through the Rayleigh–Taylor instability. In step C, when the melt becomes predominantly elastic, i.e., for $t^{*}\gtrsim {\tau }_c$ with ${\tau }_c$ the gelation point, the rotation speed is increased to ${\mathrm{\Omega }}_2$ to stretch the droplets into hairs. The rotation is finally stopped when the polymer is fully cured.