Table 1.

Physicochemical characterization data of the silica particles, both unfunctionalized and coated with polyethyleneimine (PEI).

	Size by SEM/nm	Size by DLS/nm	PDI from DLS	Zeta potential by DLS/mV	Size by DLS/nm	PDI from DLS	Zeta potential by DLS/mV	Particle number per g solid	Specific surface area/m2 g−1
	Unfunctionalized				Coated with PEI
Nanospheres	60	117	0.22	− 16	222	0.32	+ 29	4.42 × 1015	50
Submicrospheres	230	272	0.08	− 53	360	0.21	+ 36	7.85 × 1013	13
Submicrorods	125·230	357	0.23	− 29	423	0.38	+ 22	2.77 × 1014	22
Microspheres	430	519	0.15	− 28	582	0.19	+ 39	1.20 × 1013	7.0
Microrods	100·600	439	0.32	− 22	564	0.45	+ 28	1.06 × 1014	21

All particles were completely X-ray amorphous. The particle numbers and the specific surface area were computed from the SEM particle size data. DLS was performed in water at pH 7.