Abstract:
Contact angle measurement of water, benzyl alcohol, ethylene glycol and
glycerol are performed on hydrophobic surfaces of six polymers and four natural
surfaces. We performed drop impacts dynamic of water droplets on an artificial
polymer hydrophobic surfaces and natural hydrophobic surfaces with different impact
velocities. Highest spread length and oscillations were observed on both high-density
polyethylene (MI 42) and polypropylene (Bolton) due to the Wenzel regime. Two
impacts, sticking and deposition was identified on the polymer samples due to the low
static contact angles. Rebound, splashing, fragmentation and vibrational oscillations
were observed due to the micro scale roughness on the natural surfaces. Highest static
contact angle of water droplet (86.2±2.1) and lowest viscosity was obtained on
polyethylene (Mw 35k) surface. Lowest static contact angle (79.9±2.8) and highest
viscosity was observed on polypropylene surface. Furthermore, highest static contact
angle of water drop (118.02±7.46) was observed on Purple sage (Leucophyllum
frutescens) surface and lowest static contact angle (98.38±4.91) was observed on
Eucalyptus (Corymbia) surface. The viscosity and critical surface energy of the
polymer samples were also measured and discussed.
