OU NanoLab/NSF NUE/Bumm & Johnson
γ
LV
γ
LS
γ
SV
θ
V
S
L
Surface Tension:
Wetting & Contact Angle
•
Contact Angle for a Sessile Drop
•
Young’s Equation
•
Horizontal Tensions balance
•
The critical surface tension
γ
c
is an
intrinsic characteristic of the surface.
•
Liquids with
γ
<
γ
c
completely wet the
surface (
θ
= 0 º).
•
Liquids with
θ
> 90º are said to not wet the
surface (
γ
LS
>
γ
SV
)
.
•
V vapor
•
L liquid
•
S solid
•
contact angle