Adsorbed states of a long - flexible polymer chain

A phase diagram for a surface-interacting long flexible polymer chain in a two-dimensional poor solvent where the possibility of collapse exists is determined using exact enumeration method. A model of a self-attracting self avoiding walk (SASAW) on a square lattice was considered and up to 28 steps in series were evaluated. A new adsorbed state having the conformation of a surface attached globule is found. Four phases (i) desorbed expanded, (ii) desorbed collapsed, (iii) adsorbed expanded and (iv) surface attached globule are found to meet at a point on the adsorption line.