Urejanje koloidnih delcev na mehkih površinah

magistrsko delo

Tine Curk (Author), Jure Dobnikar (Mentor), Uroš Tkalec (Thesis defence commission member), Francisco J. Martinez-Veracoechea (Co-mentor)

Abstract

A grafted polymer layer can be used to prevent the deposition of colloidal particles on a solid surface. This thesis presents Monte Carlo simulations of hard-sphere colloids pushed to a polymer brush under the influence of external fields (e.g. gravity). For weak fields colloids can not penetrate the brush and the effective potential acting on a single colloid is approximately quadratic. The phase diagram of three-dimensional hard-sphere colloids, that in one dimension are constrained to a plane by a harmonic potential, is presented. Under the influence of sufficiently strong external fields colloids penetrate the brush and form internally ordered, columnar structures that span the polymer layer. The morphology of the patterns that form depends sensitively on the strength of the applied field. We propose a simple phenomenological theory that accounts for the main characteristics of the observed behaviour. The present results suggest a simple experimental method to determine the surface polymer coverage.

Keywords

Soft Matter;Monte Carlo Method;Wang-Landau Algorithm;Free Energy;Polymer Brush;Colloids;Ordering;

Data

Language:	English
Year of publishing:	2012
Source:	Maribor
Typology:	2.09 - Master's Thesis
Organization:	UM FNM - Faculty of Natural Sciences and Mathematics
Publisher:	[T. Curk]
UDC:	53(043.2)
COBISS:	19544584
Views:	1860
Downloads:	84
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary title:	Colloidal ordering on soft coated surfaces
Secondary abstract:	Polimerne krtačke varujejo površine pred adsorpcijo različnih delcev. V magistrskem delu predstavimo Monte Carlo simulacije koloidov, ki so pod vplivom zunanjih polj (npr. gravitacijskega polja) potisnjeni ob polimerno krtačko. Pri šibkih poljih koloidi ne morejo predreti krtačke in efektivni potencial, ki ga čuti posamezen koloid, je približno harmonski. Predstavljen je fazni diagram tridimenzionalnih koloidov, ki so v eni dimenziji omejeni na površino s harmonskim potencialom. Pod vplivom dovolj močnih polj lahko koloidi prodrejo v krtačko, kjer tvorijo urejene, stebraste strukture. Morfologija vzorcev, ki nastanejo, je občutljivo odvisna od poljske jakosti. Predlagamo enostavno fenomenološko teorijo, ki pojasni glavne značilnosti opaženega obnašanja. S predstavljenimi rezultati predlagamo dokaj enostavno eksperimentalno metodo za določitev površinske gostote sidranih polimerov.
Secondary keywords:	mehke snovi;metoda Monte Carlo;Wang-Landau algoritem;prosta energija;polimerna krtačka;koloidi;urejanje;magistrska dela;soft matters;Monte Carlo method;Wang-Landau algorithm;free energy;polymer brush;colloids;ordering;master theses;
URN:	URN:SI:UM:
Type (COBISS):	Master's thesis
Thesis comment:	Univ. v Mariboru, Fak. za naravoslovje in matematiko, Oddelek za fiziko
Pages:	46 f.
Keywords (UDC):	mathematics;natural sciences;naravoslovne vede;matematika;physics;fizika;
ID:	993393