1 research outputs found
Controlled Fabrication of Hexagonally Close-Packed Langmuir–Blodgett Silica Particulate Monolayers from Binary Surfactant and Solvent Systems
We describe a controllable method to fabricate hexagonally close-packed
Langmuir–Blodgett (LB) monolayers with stearic acid (SA) as
co-surfactant and methanol as co-solvent. The optimal SA concentrations
and volume ratios of chloroform to methanol are 0.8 mg/mL and 3:1
for particles of 140 nm, 0.50 mg/mL and 4:1 for particles of 300 nm,
and 0.05 mg/mL and 5:1 for particles of 550 nm, respectively. Additionally,
SEM detections of the monolayers transferred at different surface
pressures indicate that the monolayers deposited from the binary systems
are more compressible. The experimental results indicate that the
interparticle repulsions and particle–water interactions can
be enhanced without decreasing the particle hydrophobicity by adding
SA and methanol; thus, particulate monolayers with large hexagonally
close-packed domains composed of small silica particles can be successfully
fabricated using LB technique. We propose that the enhanced interparticle
repulsion is attributed to the Columbic repulsion resulting from the
attachment of SA molecules to the CTAB modified particles around the
three phase contact line