  We compare the thermodynamic behavior of a finite single nongrafted polymer
near an attractive substrate with that of a polymer grafted to that substrate.
After we recently found first-order-like signatures in the microcanonical
entropy at the adsorption transition in the nongrafted case, and given the fact
that many studies on polymer adsorption in the past have been performed for
grafted polymers, the question arises, to what extent and in what way does
grafting change the nature of the adsorption transition? This question is
tackled here using a coarse-grained off-lattice polymer model and covers not
only the adsorption transition but also all other transitions a single polymer
near an attractive substrate of varying strengths undergoes. Because of the
impact of grafting especially on the translational but also on the
conformational entropy of desorbed chains, the adsorption transition is
affected the strongest. Our results are obtained by a combined canonical and
microcanonical analysis of parallel tempering Monte Carlo data.
