Surface Forces and Friction
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Electrical Double Layer Interactions with Surface Charge Heterogeneities
Electrical double layer interactions with surface charge heterogeneities by Christian Pick A dissertation submitted to Johns Hopkins University in conformity with the requirements for the degree of Doctor of Philosophy Baltimore, Maryland October 2015 © 2015 Christian Pick All rights reserved Abstract Particle deposition at solid-liquid interfaces is a critical process in a diverse number of technological systems. The surface forces governing particle deposition are typically treated within the framework of the well-known DLVO (Derjaguin-Landau- Verwey-Overbeek) theory. DLVO theory assumes of a uniform surface charge density but real surfaces often contain chemical heterogeneities that can introduce variations in surface charge density. While numerous studies have revealed a great deal on the role of charge heterogeneities in particle deposition, direct force measurement of heterogeneously charged surfaces has remained a largely unexplored area of research. Force measurements would allow for systematic investigation into the effects of charge heterogeneities on surface forces. A significant challenge with employing force measurements of heterogeneously charged surfaces is the size of the interaction area, referred to in literature as the electrostatic zone of influence. For microparticles, the size of the zone of influence is, at most, a few hundred nanometers across. Creating a surface with well-defined patterned heterogeneities within this area is out of reach of most conventional photolithographic techniques. Here, we present a means of simultaneously scaling up the electrostatic zone of influence and performing direct force measurements with micropatterned heterogeneously charged surfaces by employing the surface forces apparatus (SFA). A technique is developed here based on the vapor deposition of an aminosilane (3- aminopropyltriethoxysilane, APTES) through elastomeric membranes to create surfaces for force measurement experiments. -
Measuring Inner Layer Capacitance with the Colloidal Probe Technique
colloids and interfaces Article Measuring Inner Layer Capacitance with the Colloidal Probe Technique Alexander M. Smith , Plinio Maroni, Michal Borkovec and Gregor Trefalt * Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30 Quai Ernest-Ansermet, 1205 Geneva, Switzerland; [email protected] (A.M.S.); [email protected] (P.M.); [email protected] (M.B.) * Correspondence: [email protected] Received: 26 October 2018; Accepted: 22 November 2018; Published: 27 November 2018 Abstract: The colloidal probe technique was used to measure the inner layer capacitance of an electrical double layer. In particular, the forces were measured between silica surfaces and sulfate latex surfaces in solutions of monovalent salts of different alkali metals. The force profiles were interpreted with Poisson-Boltzmann theory with charge regulation, whereby the diffuse layer potential and the regulation properties of the interface were obtained. While the diffuse layer potential was measured in this fashion in the past, we are able to extract the regulation properties of the inner layer, in particular, its capacitance. We find systematic trends with the type of alkali metal ion and the salt concentration. The observed trends could be caused by difference in ion hydration, variation of the binding capacitance, and changes of the effective dielectric constant within the Stern layer. Our results are in agreement with recent experiments involving the water-silica interface based on a completely independent method using X-ray photoelectron spectroscopy in a liquid microjet. This agreement confirms the validity of our approach, which further provides a means to probe other types of interfaces than silica. -
An AFM Study of the Interactions Between Colloidal Particles
An AFM study of the interactions between colloidal particles vorgelegt von Liset A. C. Lüderitz M. Sc. aus Havanna - Kuba von der Fakultät II - Mathematik und Naturwissenschaften der Technischen Universität Berlin zur Erlangung des akademischen Grades Doktor der Naturwissenschaften Dr. rer. nat. genehmigte Dissertation Promotionsausschuss: Vorsitzender: Prof. Dr. R. Schomäcker, TU Berlin Berichter: Prof. Dr. R. von Klitzing, TU Berlin Berichter: Prof. Dr. G. Papastavrou, Universität Bayreuth Tag der wissenschaftlichen Aussprache: 14.09.2012 Berlin 2012 D 83 Abstract This research project is focused on the study of the interaction forces between two col- loidal particles. The interaction between colloidal particles may differ from the interaction between macroscopic bodies. The interactions are measured across different electrolytes: CsCl, KCl, NaCl and LiCl using Colloidal Probe Atomic Force Microscope (CP-AFM) techniques. The resulting forces may be different depending on the electrolyte solution used, which is known as ion specificity. In this study no ion specificity effect is observed at long range for the adsorption of counterions to the silica surface but a slight tendency for Cs+ to be more adsorbed at the surface than the other counterions is present at 10−3 M. Deviations from the DLVO theory at small separations (non-DLVO forces) are reported in this work. Short range attractions at 10−4 M ionic strength were measured whereas at 10−3 M short range repulsions are present. An explanation of the non-DLVO forces is given based on the hydration forces. A further chapter studies the interaction forces between silicon oxide surfaces in the presence of surfactant solutions. -
Direct Force Measurements on the Colloidal Scale: from Modified Electrodes to Particle Manipulation
Direct Force Measurements on the Colloidal Scale: From Modified Electrodes to Particle Manipulation DISSERTATION zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) im Fach Chemie der Fakultät für Biologie, Chemie und Geowissenschaften der Universität Bayreuth vorgelegt von Volodymyr Kuznetsov Geboren in Stachanov Bayreuth, 2013 II III Die vorliegende Arbeit wurde an der Universität Bayreuth und der Universität Genf (Schweiz) angefertigt. Von Dezember 2008 bis April 2010 arbeitete ich am Abteilung für anorganische, analytische, und angewandte Chemie in der Universität Genf unter der Betreuung von Prof. Dr. Michal Borkovec und co-Betreuung von Prof. Dr. Georg Papastavrou; und von April 2010 bis Dezember 2012 am Lehrstuhl für Physikalische Chemie II in der Universität Bayreuth unter Betreuung von Prof. Dr. Georg Papastavrou. Vollständiger Abdruck der von der Fakultät für Biologie, Chemie und Geowissenschaften der Universität Bayreuth genehmigten Dissertation zur Erlangung des akademischen Grades Doktor der Naturwissenschaften (Dr. rer. Nat.). Amtierender Dekan: Prof. Dr. Beate Lohnert Tag des Einreichens der Dissertation: . Jan 2013 Tag des wissenschaftlichen Kolloquiums: . Feb 2013 Prüfungsausschuss: Prof. Dr. Georg Papastavrou (Erstgutachter) Prof. Dr. Andreas Fery (Zweitgutachter) IV V The larger the island of knowledge, the longer the shoreline of wonder. Ralph W. Sockman VI VII To my family VIII IX Table of Contents Summary .......................................................................................................................... -
Surface and Hydrodynamic Forces in Wetting Film
Surface and Hydrodynamic Forces in Wetting Film Lei Pan Dissertation submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy In Mining and Mineral Engineering Roe-Hoan Yoon, Chair Gerald H. Luttrell Gregory T. Adel Sunghwan Jung Alan R. Esker July 1, 2013 Blacksburg, Virginia Keywords: wetting film, hydrophobic force, hydrodynamic force, force apparatus for deformable surfaces (FADS), Frumkin-Derjaguin isotherm, combining rule Copyright © 2013 by Lei Pan Surface and Hydrodynamic Forces in Wetting Film Lei Pan ABSTRACT The process of froth flotation relies on using air bubbles to collect desired mineral particles dispersed in aqueous media on the surface, while leaving undesirous mineral particles behind. For a particle to be collected on the surface of a bubble, the thin liquid films (or wetting films) of water formed in between must rupture. According to the Frumkin-Derjaguin isotherm, it is necessary that wetting films can rupture when the disjoining pressures are negative. However, the negative disjoining pressures are difficult to measure due to the instability and short lifetimes of the films. In the present work, two new methods of determining negative disjoining pressures have been developed. One is to use the modified thin film pressure balance (TFPB) technique, and the other is to directly determine the interaction forces using the force apparatus for deformable surfaces (FADS) developed in the present work. The former is designed to obtain spatiotemporal profiles of unstable wetting films by recording the optical interference patterns. The kinetic information derived from the spatiotemporal profiles were then used to determine the disjoining pressures using an analytical expression derived in the present work on the basis of the Reynolds lubrication theory. -
Nanotribology, Surface Interactions and Characterization: an AFM Study
KTH Chemical Science and Engineering Nanotribology, Surface Interactions and Characterization: An AFM Study Rubén Álvarez-Asencio Doctoral Thesis at the KTH Royal Institute of Technology Stockholm 2014 Akademisk avhandling som med tillstånd av Kungliga Tekniska Högskolan framlägges till offentling granskning för avläggande av teknologie doctorsexamen den 13 juni 2014 kl 10 i hörstal F3, KTH Lindstedtsvägen 26, Stockholm. Avhandling presenteras på engelska. Nanotribology, Surface Interactions and Characterization: An AFM Study Rubén Álvarez-Asencio ( [email protected] ) Doctoral Thesis TRITA-CHE Report 2014:13 ISSN 1654-1081 ISBN 978-91-7595-102-7 KTH Royal Institute of Technology School of Chemical Science and Engineering Surface and Corrosion Science Drottning Kristinas väg 51 SE-100 44 Stockholm Sweden ii Denna avhandling är skyddad enligt upphovsrättslagen. Alla rättigheter förbehålles. Copyright © 2014 Rubén Álvarez-Asencio. All rights reserved. No part of this thesis may be reproduced by any means without permission from the author. The following items are reprinted with permission: Paper I: Copyright © American Chemical Society Paper II: Copyright © AIP Publishing LLC Paper III: Copyright © Springer Printed at US-AB, Stockholm 2014 iii “God grant me the serenity to accept the things I cannot change; courage to change the things I can; and wisdom to know the difference”. Reinhold Niebuhr iv To Antonio, Ángeles, Antonio-José and Alejandro v Abstract When two surfaces achieve contact, then contact phenomena such as adhesion, friction and wear can occur, which are of great interest in many disciplines, including physics, physical chemistry, material chemistry, and life and health sciences. These phenomena are largely determined by the nature and magnitude of the surface forces such as van der Waals, capillary and hydration forces. -
Understanding the Deposition and Molecular Interaction Mechanisms
Understanding the Deposition and Molecular Interaction Mechanisms of Substrate-supported Functional Coatings by Jun Huang A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Materials Engineering Department of Chemical and Materials Engineering University of Alberta © Jun Huang, 2017 Abstract Functional coatings have been extensively exploited for creating surfaces with desired functionalities in numerous engineering applications, which have received increasing attention over the past few decades. The objectives of this thesis research were to develop stable, hydrophobicity-tunable functional coatings/films and further investigate the deposition and related surface interaction mechanisms using nano-mechanical techniques such as Atomic Force Microscope (AFM) and Surface Forces Apparatus (SFA). The research has focused on four types of surface coatings, including cross-linked hydrocarbon silane (octadecyltrichlorosilane, OTCS) coating, end-grafted hydrophobic polymer (poly(pentafluorophenyl acrylate)-b-polystyrene, PPFPA-b-PS) coating, layer-by-layer deposited polyethyleneimine (PEI) and PPFPA-b-PS multi-layer coating and mussel inspired polycatecholamine (polynorepinephrine, pNE) coating. This research has revealed that the deposition process of OTCS on substrate surface with few active sites (e.g., freshly cleaved mica) via a facile vapor deposition method mainly contains two stages: silane molecules first react with the limited silanol groups forming a smooth layer and then the initial layer can serve as nucleation sites for further deposition to form cross-linked hydrocarbon coatings. The interaction forces between the as-obtained silane-functionalized mica surfaces were quantitatively measured using an SFA. It was found that the approaching force-distance profiles of the OTCS surfaces obtained via a shorter deposition time (e.g., 2 h, 8h) could be reasonably described by the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. -
Surface Force Measurements Provide Different Insights Regarding the Systems of Interests
University of Alberta A Study of Interactions of Asphaltenes in Organic Solvents Using Surface Forces Apparatus By Jinggang Xie A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Chemical Engineering ©Jinggang Xie Edmonton, Alberta Spring 2011 Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission. Library and Archives Bibliothèque et Canada Archives Canada Published Heritage Direction du Branch Patrimoine de l’édition 395 Wellington Street 395, rue Wellington Ottawa ON K1A 0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre référence ISBN: 978-0-494-70899-6 Our file Notre référence ISBN: 978-0-494-70899-6 NOTICE: AVIS: The author has granted a non- L’auteur a accordé une licence non exclusive exclusive license allowing Library and permettant à la Bibliothèque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par télécommunication ou par l’Internet, prêter, telecommunication or on the Internet, distribuer et vendre des thèses partout dans le loan, distribute and sell theses monde, à des fins commerciales ou autres, sur worldwide, for commercial or non- support microforme, papier, électronique et/ou commercial purposes, in microform, autres formats. -
Force Measurements with the Atomic Force Microscope
Surface Science Reports 59 (2005) 1–152 www.elsevier.com/locate/surfrep Force measurements with the atomic force microscope: Technique, interpretation and applications Hans-Ju¨rgen Butt a, Brunero Cappella b,*, Michael Kappl a a Max-Planck-Institute for Polymer Research, D-55128 Mainz, Germany b Federal Institute for Material Research and Testing, D-12205 Berlin, Germany Accepted 1 August 2005 Abbreviations: AFM, atomic force microscope; AOT, bis(2-ethylhexyl)sulfosuccinate; BSA, bovine serum albumin; CMC, critical micellar concentration (mol/L); CSH, calcium silicate hydrate; CTAB, cetyltrimethylammonium bromide (=hexade- cyltrimethylammonium bromide); DDAB, didodecyl dimethylammonium bromide; DDAPS, N-dodecyl-N,N-dimethyl-3- ammonio-1-propanesulfonate; DGDG, digalactosyldiglyceride; DLVO, Derjaguin–Landau–Verwey–Overbeek theory; DMA, dynamical mechanical analysis; DMT, Derjaguin–Mu¨ller–Toporov theory of mechanical contact; DNA, desoxy- ribonucleic acid; DODAB, dimethyl-dioctadecylammonium bromide; DOPC, 1,2-dioleoyl-sn-glycero-3-phosphocholine; DOPE, 1,2-dioleoyl-sn-glycero-3-phosphodylethanolamine; DOPS, 1,2-dioleoyl-sn-glycero-3-phospho-l-serine; DOTAP, 1,2-dioleoyl-3-trimethylammonium-propane chloride; DTAB, dodecyltrimethylammonium bromide; DSCG, disodium cromo- glycate; DSPE, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine; EDTA, ethylenediaminetetraacetic acid; FJC, freely jointed chain; HOPG, highly oriented pyrolytic graphite; HSA, human serum albumin; JKR, Johnson–Kendall–Roberts theory of mechanical contact; LPS, lipopolysaccharides;