Shear forces on covalently cross-linked polymer nanowires. Nanoscale polymer structures are promising candidates as new nanoscale engineering materials owing to their tunable mechanical properties that arise from their nanoscale size, and they are being synthesized using a variety of cross-linking strategies that exploit their chemical functionality. Here we measure the compressive uniaxial tensile strength of covalently cross-linked semicrystalline poly(ethylene glycol) nanowires (NWs) synthesized via an oxidative hydrolysis of thiol-ene ring-forming reactions with a polymer which is cross-linked by a bis-diphenyl-diselenide moiety. We synthesize two polymer NWs with differing degrees of cross-linking: (i) a relatively linear polymer with low cross-link density and (ii) a relatively rigid polymer with high cross-link density. We find that for both types of nanowire, the tensile strengths are insensitive to the degree of cross-linking and are independent of the degree of crystallinity of the polymer as long as the degree of cross-linking is moderate. We use a micromechanical model to analyze the effective stress of the two NWs as a function of wire radius. We find that the effective stress of both the low- and high-cross-link density NWs decreases with decreasing radius, which agrees with the observed mechanical properties of the NWs..2016, Sep. 17, 2017. The left panel shows the time-series of the SSA index, and the right panel shows the time-series of the KARMA index. []{data-label=”fig:karma_ssa”}](sma_karma_2d_up.pdf “fig:”){width=”49.00000%”}![The left panel shows the time-series of the SSA index, and the right panel shows the time-series of the KARMA index. []{data-label=”fig:karma_ssa”}](karma_ssa_2d_up.pdf “fig:”){width=”49.00000%”} ![Probability distribution of the SSA index for $t=0.1\cdot 10^3$. []{data-label=”fig:karma_ssa_pdf”}](sma_ssa_pdf_0.1e3