  The role of solvent quality in determining the universal material properties
of dilute polymer solutions undergoing steady simple shear flow is examined. A
bead-spring chain representation of the polymer molecule is used, and the
influence of solvent molecules on polymer conformations is modelled by a narrow
Gaussian excluded volume potential that acts pair-wise between the beads of the
chain. Brownian dynamics simulations data, acquired for chains of finite
length, and extrapolated to the limit of infinite chain length, are shown to be
model independent. This feature of the narrow Gaussian potential, which leads
to results identical to a $\delta$-function repulsive potential, enables the
prediction of both universal crossover scaling functions and asymptotic
behavior in the excluded volume limit. Universal viscometric functions,
obtained by this procedure, are found to exhibit increased shear thinning with
increasing solvent quality. In the excluded volume limit, they are found to
obey power law scaling with the characteristic shear rate $\beta$, in close
agreement with previously obtained renormalization group results. The presence
of excluded volume interactions is also shown to lead to a weakening of the
alignment of the polymer chain with the flow direction.
