Dynamics of Polymer Adsorption from Bulk Solution onto Planar Surfaces

Abstract

Polymer adsorption of uncharged homopolymers onto planar surfaces has been investigated by employing a coarse-grained bead-spring polymer model using simulation techniques. Polymer solutions of two different densities and polymers of two different contour lengths have been examined. The dynamics of the adsorption process appearing in systems composed of a polymer solution placed near attractive, but initially polymer-free, surfaces were determined by Brownian dynamics simulations and equilibrium properties of corresponding systems by Monte Carlo simulations. The properties of the systems have been analyzed by monitoring the number of adsorbed polymers, bead density profiles, time and frequency of polymer attachments, spatial extension of polymers perpendicular and parallel to the surface, and configurational characteristics. Initially, the polymers diffuse toward the surfaces, and at shorter distances the attractive surface potential starts to pull the polymers toward the surface, making them slightly stretched perpendicular to the surface. Thereafter, the polymers collapse onto the surface with multiple anchoring, and a slower relaxation increasing the extension of the polymers parallel to the surfaces appears. Finally, at even longer times, and connected to the slow relaxation of the number of adsorbed polymers, the extension of the polymer coils parallel to the surface is reduced, and the perpendicular extension is increased, with associated changes of the number of beads residing in tails, loop, and trains. The adsorption process becomes faster at decreasing polymer length and at increasing polymer density.

Effects of carbon nanotubes on polymer physics

“…STM allows the determination of the chiral angle and the polymer spacing along the nanotube. For DNA and a (6,5) tube the angle and distance were $63 and $3.3 nm, respectively, which agreed well with computer simulations of the structure. For poly(3-hexylthiophene) the angle and distance were $45 and $1.7 nm, respectively.…”

“…This change is quantified by the radius of gyration in the parallel direction relative to that in the perpendicular direction. Simulations 5,6 indicate that the radius of gyration in the perpendicular directions can be 1-2 orders of magnitude lower than that in the parallel direction; however the three-dimensional radius of gyration, which is easily measurable, will show little change because the sum of the square of the two radii of gyration is approximately constant.…”

Influence of the molecular architecture on the adsorption onto solid surfaces: comb-like polymers

“…30 There are several theoretical studies in the literature available on this topic. [31][32][33] However, there are substantial problems in studying the kinetics of the process experimentally in a very short time scale. [34][35][36] The kinetic data presented below can be described as those from a bimodal process in the way proposed by Chiang et al 37 Our data agree with the results previously reported for other polyelectrolyte systems.…”

Staining proteins: A simple method to increase the sensitivity of ellipsometric measurements in adsorption studies

“…Adsorption of synthetic polymers and proteins to solid surfaces is of interest for many industrial and biomedical applications [1-4]. Aiming to understand the driving forces of such interactions, adsorption processes have been studied with a variety of techniques [5] including reflectometry [6], quartz crystal microbalance [7], atomic force microscopy [8], and fluorescence microscopy [9].…”