Fluoroalkylsilane versus Alkylsilane as Hydrophobic Agents for Silica and Silicates

Table 4

Chemical composition and degree of coverage of both unmodified and grafted magnesium silicate.

Sample	Content						Degree of coverage; (μmol/m^2)
	Elemental analysis		XPS
	C (%)	H (%)	O (% atm.)	F (% atm.)	Si (% atm.)	Mg (% atm.)
MgO·SiO2	—	3.03	63.29	—	21.90	8.00	—
MgO·SiO2 + 3 wt./wt. of OPF	1.57	2.78	59.88	3.12	19.67	7.09	0.21
MgO·SiO2 + 5 wt./wt. of OPF	1.95	2.86	57.82	4.51	17.35	7.42	0.25
MgO·SiO2 + 10 wt./wt. of OPF	2.29	2.98	50.34	8.07	19.31	7.21	0.30
MgO·SiO2 + 3 wt./wt. of ODS	1.90	3.06	56.78	Not determined	19.10	7.11	0.17
MgO·SiO2 + 5 wt./wt. of ODS	2.14	3.13	58.35		20.50	7.71	0.17
MgO·SiO2 + 10 wt./wt. of ODS	3.59	3.29	59.98		22.05	7.99	0.21
MgO·SiO2 + 3 wt./wt. of OCS	1.02	2.46	59.78		19.87	7.10	0.20
MgO·SiO2 + 5 wt./wt. of OCS	1.25	2.73	62.10		21.33	8.45	0.22
MgO·SiO2 + 10 wt./wt. of OCS	1.58	2.97	65.34		24.56	9.98	0.26