Adsorption Phenomena of Polyelectrolyte Dispersants on α-Alumina Surfaces
Date Issued
2005
Date
2005
Author(s)
Chen, Hsin-Yi
DOI
en-US
Abstract
This study presents a simulation procedure and demonstrates the simulation results in comparison with the adsorption of polymers by atomic force microscopy (AFM) experiment. The adsorption process of dispersants interplay with α-Al2O3 surfaces, adsorbed conformations, and the steric potential interaction are of interest. The procedure employed molecular dynamics (MD) techniques to execute simulations on the interactions of polyacrylic acid (PAA), polymethacrylic acid (PMA), polymethyl methacrylate (PMMA), polyethylene (PE), and Poly 2-Acrylamido-2-methylpropane sulfonic acid-co-Methacrylic acid-co-(β-carboxylate (hydroxyl acrylic polyethylester))) (PAMC) polymers with various dissociated fraction, 0.1、0.5、1, with O- or Al-terminated on , , , , and planes of Al2O3 surfaces, which were constructed in nano-scale thickness (ca. 1~1.3 nm). Ten parameters, i.e., optimal thickness, Al2O3 planes, termination, functional groups, molecular weight, dissociated fraction, chain numbers, medium, and the pH effects on steric force between two surfaces has been studied.
Direct measurements of the interaction forces between Al2O3 surfaces by AFM in the absence and presence of low-molecular-weight (MW = 5000) poly (acrylic acid) (PAA) were conducted at different pH solutions. The measurement at high pH where the adsorbed, highly charged anionic polyelectrolyte extends into the solution, leads to a combination of steric and electrostatic interactions. The buildup of PAA at the interface is closely related to manifest attractive bridging interactions, adhesion, during approaching route. The force results are compared the MD simulation by the same dispersant. In the next section, comparing different polyelectrolytes to observe the factor to dispersion is proceeding. Eventually, our destination is to predict the better dispersants by simulation in lieu of synthesis.
Subjects
分子動力學模擬
原子力顯微鏡 (AFM)
α-Al2O3
分散劑
吸附
PAA
PMA
PMMA
PE
PAMC
Alumina
Dispersant
adsorption
Molecular dynamics (MD) simulation
Atomic force microscopy (AFM)
Type
thesis
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