Advances in Contact Angle, Wettability and Adhesion, Volume 3

K. L. Mittal

• Publisher: Wiley-Scrivener
• Year: 2018
• Print ISBN: 9781119459941
• eBook ISBN: 9781119459958
• Edition: 1
• Topic: Tecnologia e ingegneria
• Subtopic: Scienza dei materiali

With 16 chapters from world-renowned researchers, this book offers an extraordinary commentary on the burgeoning current research activity in contact angle and wettability

The present volume constitutes Volume 3 in the ongoing series Advances in Contact Angle, Wettability and Adhesion which was conceived with the intent to provide periodic updates on the research activity and salient developments in the fascinating arena of contact angle, wettability and adhesion.

The book is divided into four parts: Part 1: Contact Angle Measurement and Analysis; Part 2: Wettability Behavior; Part 3: Superhydrophobic Surfaces; Part 4: Wettability, Surface Free Energy and Adhesion. The topics covered include: procedure to measure and analyse contact angle/drop shape behaviors; contact angle measurement considering spreading, evaporation and reactive substrate; measurement of contact angle of a liquid on a substrate of the same liquid; evolution of axisymmetric droplet shape parameters; interfacial modulus of a solid surface; functionalization of textiles using UV-based techniques for surface modification--patterned wetting behavior; wettability behavior of oleophilic and oleophobic nanorough surfaces; wettability behavior of nanofluids; dielectrowetting for digital microfluidics; hydrophobicity and superhydrophobicity in fouling prevention; superhydrophobic/superhydrophilic hybrid surface; determination of the surface free energy of solid surfaces: statistical considerations; determination of apparent surface free energy using hysteresis approach; wettability correlations for bioadhesion to different materials; laser material processing for enhancing stem cell adhesion and growth.

Part 1
CONTACT ANGLE MEASUREMENT AND ANALYSIS

Chapter 1
A More Appropriate Procedure to Measure and Analyse Contact Angles/Drop Shape Behaviours

M. Schmitt^1,2,3* and F. Heib³

¹Institut de Science des Matériaux de Mulhouse IS2M, UMR CNRS 7361, UHA; Mulhouse Cedex, France

²Institut for Coatings and Surface Chemistry, Niederrhein University of Applied Science, Krefeld, Germany

³Saarland University, Physical Chemistry, Saarbrücken, Germany

^*Corresponding author: [email protected]

Abstract

Surface science, which comprises the preparation, development and analysis of surfaces, is of utmost importance in both fundamental and applied sciences as well as in engineering and industrial research. During our research in the field of coatings/surfaces and coating materials, the analyses of wetting of coating materials and the coatings themselves led us to the field of dynamically performed drop shape analysis. We focussed our research efforts on the main problem of the surface science community, which is to determine the correct and valid definition and measurement of contact angles. So we developed the high-precision drop shape analysis (HPDSA) and three statistical contact angle determination procedures. HPDSA involves complex transformation of images from dynamic sessile drop experiments to x-y-coordinates and opens up the possibility of a physically meaningful calculation of curvature radii. This calculation of radii is the first step to an “assumption-free” link to the Laplace equation, which can deepen the understanding of the interface between the liquid and the vapour in relation to different properties and conditions (temperature, experimental technique, surface, etc.). The additional benefit of a tangent-free calculation of contact angles is presented in our 2014 and 2016 published papers. To fulfil the dire need for a reproducible contact angle determination/definition, we developed three procedures, namely, overall, global, and individual statistical analyses, which are based on, but not restricted to, HPDSA so that the procedures can be implemented to analyse contact angle data from commercial software. During the process of development we investigated wetting of ideal surfaces, contact angle hysteresis, dynamics of wetting, wetting of rough and chemically heterogeneous surfaces, the Wenzel and Cassie models, superhydrophobicity, superhydrophilicity and the rose petal effect, wetting transitions on rough surfaces, nonstick droplets, effects of ionic liquids (sticking droplets), etc..

Keywords: HPDSA, contact angle, advancing angle, receding angle, wetting, drop shape, hydrophobic, hydrophilic, superhydrophobic, statistical contact angle

1.1 Introduction

This chapter summarizes our “drop-related” research of the recent years until 2016 [1–13], Scheme 1.1, i.e. the drop shape analysis or, more specifically, the analysis of the dynamic drop shape behaviour, where the current focus is on contact angle (CA) measurements and analyses. Thus, this chapter deals with a stable and fast super-resolution image analysis in combination with a contour/radii calculation, and a suggested combination with one or all three statistical procedures presented to analyse contact angle data. This topic of our investigations can briefly be summarised by “wetting”. Wetting as an effect describing the contact between solid and liquid phases is important for life and nearly every application. For example, good wetting is a necessary but not a sufficient condition for the coating material to form a well-adhered coating (completely well-bonded coating without defects).

Scheme 1.1 Summary and history of the methods developed and their applications. Development of the super-resolution drop shape analysis is mainly focused in contribution [3], the application/development of the statistical CA analyses was finally developed/conceived in contribution [9]. The aims of statistical procedures are inter alia reproducible CA definitions (advancing/receding, up-/downhill) and motion behaviour analysis. Uncited applications are experimentally confirmed but not published, and applications and questions in dashed boxes are most likely possible but due to hardware or time aspects were not performed until now.

1.1.1 Brief Summary of the ...

Table of contents

• Cover
• Title page
• Copyright page
• Preface
• Part 1: Contact Angle Measurement and Analysis
• Part 2: Wettability Behavior
• Part 3: Superhydrophobic Surfaces
• Part 4: Wettability, Surface Free Energy and Adhesion
• Index
• End User License Agreement