Soft matter lubrication: does solid viscoelasticity matter?
File(s)acsami.7b09381.pdf (4.62 MB)
Published version
Author(s)
Putignano
Dini, D
Type
Journal Article
Abstract
Classical lubrication theory is unable to explain a variety of phenomena and experimental observations involving soft viscoelastic materials, which are ubiquitous and increasingly used in e.g. engineering and biomedical applications. These include unexpected ruptures of the lubricating film and a friction–speed dependence, which cannot be elucidated by means of conventional models, based on time-independent stress–strain constitutive laws for the lubricated solids. A new modeling framework, corroborated through experimental measurements enabled via an interferometric technique, is proposed to address these issues: Solid/fluid interactions are captured thanks to a coupling strategy that makes it possible to study the effect that solid viscoelasticity has on fluid film lubrication. It is shown that a newly defined visco-elasto-hydrodynamic lubrication (VEHL) regime can be experienced depending on the degree of coupling between the fluid flow and the solid hysteretic response. Pressure distributions show a marked asymmetry with a peak at the flow inlet, and correspondingly, the film thickness reveals a pronounced shrinkage at the flow outlet; friction is heavily influenced by the viscoelastic hysteresis which is experienced in addition to the viscous losses. These features show significant differences with respect to the classical elasto-hydrodynamic lubrication (EHL) regime response that would be predicted when solid viscoelasticity is neglected. A simple yet powerful criterion to assess the importance of viscoelastic solid contributions to soft matter lubrication is finally proposed.
Date Issued
2017-11-07
Date Acceptance
2017-11-06
Citation
ACS Applied Materials and Interfaces, 2017, 9 (48), pp.42287-42295
ISSN
1944-8244
Publisher
American Chemical Society
Start Page
42287
End Page
42295
Journal / Book Title
ACS Applied Materials and Interfaces
Volume
9
Issue
48
Copyright Statement
This is an open access article published under a Creative Commons Attribution (CC-BY)
License, which permits unrestricted use, distribution and reproduction in any medium,
provided the author and source are cited.
License, which permits unrestricted use, distribution and reproduction in any medium,
provided the author and source are cited.
License URL
Sponsor
Commission of the European Communities
Engineering & Physical Science Research Council (EPSRC)
Identifier
https://pubs.acs.org/doi/10.1021/acsami.7b09381
Grant Number
PIEF-GA-2013-622632
EP/N025954/1
Subjects
Science & Technology
Technology
Nanoscience & Nanotechnology
Materials Science, Multidisciplinary
Science & Technology - Other Topics
Materials Science
lubrication
viscoelasticity
friction
MECHANICS
FRICTION
CONTACTS
POLYMERS
SURFACES
friction
lubrication
viscoelasticity
03 Chemical Sciences
09 Engineering
Nanoscience & Nanotechnology
Publication Status
Published
Date Publish Online
2017-11-17