Table 1.

Sizes and zeta-potentials of different silica nanoparticles in 1:1 water-ethanol medium^a.

GPTMS addition time (min)	Hydrodynamic size (nm)	TEM size (nm)	Zeta Potential (mV)
5	198	105	−55.2 (±5)
10	226	140	−46.1 (±3)
15	201	162	−39.7 (±1)
20	314	235	−30.5 (±1)
30	332	280	−35.3 (±2)
SiNP Bhakta method	450	385	−62.5 (±3)
SiNP Bhakta method − GPTMS grafted	461	386	−56.3 (±2)

^aTetraethylorthosilicate concentration was 90 mM and GPMS concentration was 50 mM.