When deposited from a solution onto a surface, superpolymeric chains display revealing transitions in their apparent stiffness. With simulated chains in adsorption, we varied the backbone rigidity and measured the chain persistence length (l(Pads)). As the three-dimensional persistence length (l(P3)) increases toward the contour length, a transition can be seen from l(Pads) = l(P2) (i.e., the two-dimensional persistence length) to l(Pads) = l(P3). Looped conformations decrease in frequency with a distinct nonlinear dependence. Finally, comparisons with experiments on polymeric worm micelles and purified neurofilaments demonstrate a simple new method for assessing the flexibility of these novel superpolymers. (C) 2004 Wiley Periodicals, Inc.