Fluoroalkylsilane versus Alkylsilane as Hydrophobic Agents for Silica and Silicates

Table 3

Chemical composition and degree of coverage of both unmodified and grafted silica.

Sample	Content					Degree of coverage; (μmol/m^2)
	Elemental analysis		XPS
	C (%)	H (%)	O (% atm.)	F (% atm.)	Si (% atm.)
SiO2	1.72	1.46	54.21	—	24.98	—
SiO2 + 3 wt./wt. of OPF	2.17	1.57	48.51	11.12	22.91	4.53
SiO2 + 5 wt./wt. of OPF	2.57	1.67	42.97	17.85	19.64	5.24
SiO2 + 10 wt./wt. of OPF	3.27	1.67	39.25	23.10	18.81	7.61
SiO2 + 3 wt./wt. of ODS	2.80	1.54	38.98	Not determined	19.87	3.74
SiO2 + 5 wt./wt. of ODS	4.30	1.85	42.83		21.59	4.14
SiO2 + 10 wt./wt. of ODS	6.27	2.36	45.79		24.65	4.78
SiO2 + 3 wt./wt. of OCS	2.25	1.87	48.78		22.68	4.48
SiO2 + 5 wt./wt. of OCS	2.59	1.98	50.57		24.82	4.65
SiO2 + 10 wt./wt. of OCS	3.08	2.00	53.78		27.98	5.20