  We use non-equilibrium atomistic molecular dynamics simulations of
unentangled melts of linear and star polymers ($\mathrm{C_{25}H_{52}}$) to
study the steady-state viscoelastic response under confinement within nanoscale
hematite $\left ( \mathrm{\alpha-Fe_2O_3} \right )$ channels. We report (i) the
negative (positive) first (second) normal stress difference and (ii) the
presence of viscoelastic tension at low shear rates. We link these effects to
bond alignment such that chains near the surface can carry the elastic force
exerted on the walls, which decays as the chains become more aligned in the
flow direction as the shear rate increases.
