Table 4. Advancing and Receding Contact Angle of Milli-Q Water and C₈-Saturated Milli-Q Water Droplets on Calcite and Carboxylic Acid-Modified Calcite^a.

Droplet	Surface	Advancing CA, θa	Receding CA 1, θr	Receding CA 2, θr	Fp 1 (mN m–1)	Fp 2 (mN m–1)
H2O	C8-modified	109 ± 3°	41°	15°	4.9	6.8
	C18-modified	106 ± 4°	69°	-	2.7	-
C8-saturated H2O	Freshly fractured calcite	70 ± 1°	58°	47°	0.38	0.35
	C8-modified	71 ± 2°	62°	53°	0.28	0.28
	C18-modified	74 ± 1°	60°	55°	0.44	0.16

^aThe advancing CA is an average value obtained during the first 5 s when the contact line starts to advance. Receding CA 1 reflects the CA when the droplet BD starts to decrease, while receding CA 2 is evaluated when the droplet BD stabilizes and remains constant for some time. The resulting pinning force, F_p, values were calculated as: F_p = γ_LV(cos θ_a – cos θ_r), where the liquid–vapor surface tension γ_LV can be found in Table 2, and θ_a and θ_r are the advancing and retreating CAs, respectively.