Thermal Behavior and structural evolution of silica nanospheres synthesized at controlled ammonia concentration and temperature
Year: 2026
Type: article
Abstract: This study examined how synthesis temperature and reagent formulation were related to morphology, electrokinetic behavior, and thermal evolution of Stöber silica in a 4 × 4 synthesis matrix. Characterization included scanning electron microscopy (SEM) with equivalent-circle-diameter (ECD) analysis, dynamic light scattering (DLS), zeta-potential and conductivity measurements, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and thermogravimetry/differential scanning calorimetry coupled with quadrupole mass spectrometry (TG/DSC-QMS). Mean ECD values ranged from 108 to 1015 nm, with the largest corresponding to coalesced structures. Higher nominal NH 4 OH concentrations were associated with larger objects. At higher NH 4 OH concentrations, increasing temperature was associated with smaller particles, narrower SEM-ECD distributions, and fewer coalesced structures. DLS followed the SEM particle-size trend. Samples prepared at 0.150 mol L −1 NH 4 OH formed the smallest particles, had natural suspension pH values of 5.8–6.1 and zeta potentials of −21.27 to −30.07 mV, and showed lower mass-normalized m/z 18 areas at 30–250 °C (4.18–6.63 A s mg −1 ) than the remaining samples (8.42–11.77 A s mg −1 ). They also showed stronger low-temperature organic-fragment signals, particularly at m/z 31. TG mass losses were 4.31–6.50%, 3.98–5.59%, and 0.66–1.00% at 30–250, 250–600, and 600–1000 °C, respectively. After calcination at 1000 °C, hydroxyl-, water-, and C–H-related bands were below the ATR-FTIR detection limit, while Si–O–Si band changes were consistent with further network condensation. Overall, this distinct cross-technique grouping links synthesis conditions with electrokinetic and thermal behavior relevant to subsequent dispersion, calcination, and surface functionalization.
Institution: AGH University of Krakow
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,790
OpenAlex ID: W7225779176