Measurement of the effect of high-power ultrasound on wetting of paper.
High-power ultrasound has been known to promote penetration of liquids into porous materials. This work presents results of experimental investigations of the influence of 40 kHz high-power ultrasound on wetting processes of papers. Wetting was monitored by the measurement of the attenuation of 0.5-9 MHz ultrasound transmitted through the immersed sample. The samples were sized papers with contact angles 40 degrees, 70 degrees and 110 degrees, and the immersion liquids were isopropanol-water mixtures of 0-100% isopropanol concentration. The investigation showed that application of high-power ultrasound resulted in faster sorption processes. However, the absolute reduction in time to reach the stationary state was not very great.
Stor-Pellinen
J
J
Department of Physics, University of Helsinki, Finland. jyrki.stor-pellinen@helsinki.fi
Haeggström
E
E
Luukkala
M
M