2.1 Sol-Gel Process
Sol-gel synthesis creates materials from liquid precursors through hydrolysis and condensation reactions.
π Hydrolysis and Condensation:
$$Si(OR)_4 + 4H_2O \rightarrow Si(OH)_4 + 4ROH$$
$$Si(OH)_4 \rightarrow SiO_2 + 2H_2O$$
π» Code Example 1: Sol-Gel Gelation Modeling
# Requirements:
# - Python 3.9+
# - matplotlib>=3.7.0
# - numpy>=1.24.0, <2.0.0
import numpy as np
import matplotlib.pyplot as plt
def solgel_gelation_time(pH, temp):
"""Model gelation time"""
T = temp + 273
t_gel = 100 * np.exp(0.5*(pH-7)**2) * np.exp(5000/(8.314*T))
return t_gel
pH_vals = np.linspace(1, 13, 100)
t = [solgel_gelation_time(pH, 60) for pH in pH_vals]
plt.semilogy(pH_vals, t, 'b-', linewidth=2)
plt.xlabel('pH')
plt.ylabel('Gelation Time (min)')
plt.grid(True, alpha=0.3)
plt.show()2.2 Hydrothermal Synthesis
Hydrothermal methods use high-temperature aqueous solutions in autoclave for crystal growth.
π» Code Example 2-7: Full Process Control
# Particle size control, temperature effects, nucleation kinetics
# Morphology control, composition tuning, characterization
# See complete implementations in full chapterSummary
- Sol-gel: molecular-level mixing, low temperature processing
- Hydrothermal: crystalline materials from aqueous solutions
- Precipitation: controlled nucleation and growth
- Applications: nanoparticles, catalysts, bioceramics