Continuum random sequential adsorption of polymer on a flat and homogeneous surface

Abstract

Random Sequential Adsorption (RSA) of polymer, modeled as a chain of identical spheres, is systematically studied. In order to control precisely anisotropy and number of degrees of freedom, two different kinds of polymers are used. In the first one, monomers are placed along a straight line; whereas in the second, relative orientations of particles are random. Such polymers fill a flat homogeneous surface randomly. The paper focuses on maximal random coverage ratio and adsorption kinetics dependence on polymer size, shape anisotropy and numbers of degrees of freedom.Obtained results were discussed and compared with other numerical experiments and theoretical predictions.

Properties of random sequential adsorption of generalized dimers

“…The above relation, known as Feder's law, has been also proved numerically for one-to eightdimensional collectors [23] as well as for fractal collectors having 1 < d < 3 [24,25]. It is also valid for RSA of anisotropic particles on a flat collector [7,12,26,27], however, in this case, d = 3, which could be explained by additional degree of freedom of an adsorbate particle [6,[28][29][30]. In our case, the power law (4) is fulfilled for all studied particles (see Fig.3).…”

“…The minimum is reached around ǫ = 1.5 when particles disks are separated, but the distance between them is too small to be filled up by another molecule. For [23,30]. ǫ = 2, it becomes possible, so the next local maximum is reached.…”

Shapes for maximal coverage for two-dimensional random sequential adsorption

“…The properties of packings generated by RSA algorithm have been checked for a number of different particle shapes, e.g., spheres 3,14,15 , spherocylinders and ellipsoids 16,17 , rectangles 18,19 , and polymers 20,21 . Results obtained for anisotropic particles show that saturated random coverage fraction reaches its maximum for moderate anisotropy, i.e., when long-to-short particle axis ratio is approximately 1.5-2.0 16,19 .…”

Random sequential adsorption of starlike particles

“…For RSA ol disks on a surface, d = 2. Equation (2), known as Feder's law, was proved to be valid not only for spherically symmetric particles, though d = 3 for elongated object [9,11,14], and, in general, it is interpreted as the number of a particle's degrees of freedom [31,32], Feder's law is also valid for surfaceless objects [13,19] but its interpretation does not hold anymore. For example, in the case of RSA of needles d is negative [13] because N(t) can grow unlimitedly.…”