title: Canonical and microcanonical analysis of nongrafted homopolymer adsorption by an attractive substrate.
abstract: Using the off-lattice Monte Carlo simulation and replica-exchange method, we studied the behavior of nongrafted homopolymer adsorption by an attractive substrate from both the canonical and the microcanonical views. An adsorption transition is identified from the peak in canonical specific heat and compared with the conventional polymer adsorption with one end anchored on the surface of the substrate. Judging from the typical "backbending effect" and the negative specific heat in microcanonical ensemble, the transition is first-order-like when adsorption is relatively strong. However, it becomes second-order-like when the strength of adsorption becomes weak enough. Further study reveals that for a chain consisting of a limited number of monomers, the type of this transition becoming either first- or second-order-like depends not only on the interplay between monomer-monomer and monomer-substrate interaction, but also on the width of the gap in which it is confined.
authors.affiliation: Department of Polymer Science and Engineering, CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.forename: Xiangsong
authors.initials: X
authors.lastname: Lin
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Haojun
authors.initials: H
authors.lastname: Liang
mesh_terms: D000327:Adsorption; D019277:Entropy; D008958:Models, Molecular; D008968:Molecular Conformation; D011108:Polymers / Q000737:chemistry*
chemical_list: D011108:Polymers