| 69786 |
Creator |
c3baa1aae2495d9fcf383c433b46bfe0 |
| 69786 |
Creator |
ext-ba46cf9d428654ebdc699f2cbc52f8fd |
| 69786 |
Date |
2020 |
| 69786 |
Is Part Of |
repository |
| 69786 |
Is Part Of |
p25045377 |
| 69786 |
abstract |
A closed form expression capable of predicting the evolution of the shape of liquid
capillary bridges and the resultant force between parallel platens is derived. Such
a scenario occurs within many micro-mechanical structures and devices, for example,
in micro-squeeze flow rheometers used to ascertain the rheological properties of pico-
to nano-litre volumes of complex fluids, which is an important task for the analysis
of biological liquids and during the combinatorial polymer synthesis of healthcare
and personal products. These liquid bridges exhibit capillary forces that can perturb
the desired rheological forces, and perhaps more significantly, determine the geometry
of the experiment. The liquid bridge has a curved profile characterised by a contact
angleat the three-phase interface, as compared to the simple cylindrical geometry
assumed during the rheological analysis. During rheometry, the geometry of the bridge
will change in a complex nonlinear fashion, an issue compounded by the contact angle
undergoing hysteresis. Owing to the small volumes involved, ascertaining the bridge
geometry visually during experiment is very difficult. Similarly, the governing equations
for the bridge geometry are highly nonlinear, precluding an exact analytical solution,
hence requiring a substantial numerical solution.
Here, an expression for the bridge geometry and capillary forces based on the toroidal
approximation has been developed that allows the solution to be determined several
orders of magnitude faster using simpler techniques than numerical or experimental
methods. This expression has been applied to squeeze-flow rheometry to show how the
theory proposed here is consistent with the assumptions used within rheometry. The
validity of the theory has been shown through comparison with the exact numerical
solution of the governing equations. The numerical solution for the shape of liquid
bridges between parallel platens is provided here for the first time and is based
on existing work of liquid bridges between spheres. |
| 69786 |
authorList |
authors |
| 69786 |
issue |
1 |
| 69786 |
status |
peerReviewed |
| 69786 |
uri |
http://data.open.ac.uk/oro/document/1092726 |
| 69786 |
uri |
http://data.open.ac.uk/oro/document/1092727 |
| 69786 |
uri |
http://data.open.ac.uk/oro/document/1092728 |
| 69786 |
uri |
http://data.open.ac.uk/oro/document/1092729 |
| 69786 |
uri |
http://data.open.ac.uk/oro/document/1092730 |
| 69786 |
uri |
http://data.open.ac.uk/oro/document/1092731 |
| 69786 |
uri |
http://data.open.ac.uk/oro/document/1096320 |
| 69786 |
volume |
4 |
| 69786 |
type |
AcademicArticle |
| 69786 |
type |
Article |
| 69786 |
label |
Bowen, James and Cheneler, David (2020). Closed-Form Expressions for Contact Angle
Hysteresis: Capillary Bridges between Parallel Platens. Colloids and Interfaces,
4(1), article no. 13. |
| 69786 |
Title |
Closed-Form Expressions for Contact Angle Hysteresis: Capillary Bridges between Parallel
Platens |
| 69786 |
in dataset |
oro |