Contact Mechanics of UV/Ozone-Treated PDMS by AFM and JKR Testing: Mechanical Performance from Nano- to Micrometer Length Scales
Jing Song
Davide Tranchida
G. Julius Vancso
10.1021/ma800536y.s001
https://acs.figshare.com/articles/journal_contribution/Contact_Mechanics_of_UV_Ozone_Treated_PDMS_by_AFM_and_JKR_Testing_Mechanical_Performance_from_Nano_to_Micrometer_Length_Scales/2912239
The Young’s modulus of cross-linked poly(dimethylsiloxane) (PDMS) surface was quantitatively investigated as a function of UV/ozone treatment time across different length scales. An AFM was used to probe PDMS surface mechanical properties at the nanometer length scale. The Young’s modulus of each sample was estimated with continuum contact mechanics theory (Sneddon method) using AFM data by employing the hyperboloid tip shape model. A custom-built ATD device (JKR method) was also used which allowed us to simultaneously monitor the load, the contact area, and the relative displacement between (a) a lens (made either of PDMS elastomer or of Si<sub>3</sub>N<sub>4</sub>) and (b) surface-treated PDMS films upon loading and unloading on the micrometer to submillimeter length scales. The modulus of PDMS increased with increasing treatment time as observed by AFM as well as by ATD, which we explained by the gradual formation of a silica-like layer. For all specimens tested, the modulus values obtained were highest from AFM, lower from ATD, and lowest from bulk tensile experiments for the same UV/ozone dose. These results demonstrate the effect of the probed length scale of the tests used to assess mechanical performance.
2008-09-23 00:00:00
PDMS elastomer
hyperboloid tip shape model
probe PDMS surface
nanometer length scale
Si 3N
treatment time
JKR method
UV
ATD device
AFM data
continuum contact mechanics theory
Sneddon method
Mechanical Performance
length scales
contact area
length scale
modulus values
Contact Mechanics
JKR Testing
submillimeter length scales