“…The situation can be adapted to model the adsorption of linear polymers at an impenetrable surface [5,10,15,23] and the general features of the adsorption behaviour are now quite well understood. With the invention of micro-manipulation techniques such as atomic force microscopy (AFM) and optical tweezers that allow individual polymer molecules to be pulled [7,26] there has been renewed interest in how polymers respond to a force and, specifically, how self-avoiding walk models of polymers respond to a force [1,2,8,9,14,17]. There has also been some work on how lattice polygons (a model of ring polymers) respond to a force [2,12,13].…”