Controlled Fabrication of Hexagonally Close-Packed Langmuir鈥揃lodgett Silica Particulate Monolayers from Binary Surfactant and Solvent Systems

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• 作者：Yudi Guo ; Dongyan Tang ; Yunchen Du ; Binbin Liu
• 刊名：Langmuir
• 出版年：2013
• 出版时间：March 5, 2013
• 年：2013
• 卷：29
• 期：9
• 页码：2849-2858
• 全文大小：624K
• 年卷期：v.29,no.9(March 5, 2013)
• ISSN：1520-5827

文摘

We describe a controllable method to fabricate hexagonally close-packed Langmuir鈥揃lodgett (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鈥搘ater 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.