Surface Behavior and Buckling of Silver Interfacial Colloid Films

We study the surface behavior of Langmuir films of highly concentrated interfacial colloids composed of flocculated silver nanoparticles located at the liquid−liquid interface of water and dichloromethane. Pressure/area isotherms and UV−visible absorption−reflection spectra are acquired in situ simultaneously. The behavior is discussed in terms of the colloid particle size and concentration. A reversible buckling of the film is observed at about 20−22 erg/cm 2, with a creased three-dimensional phase replacing the smooth two-dimensional phase. The temperature dependence of the π/ A curves is measured and discussed, particularly in relation to the buckling of the film. This work bridges over the size gap between the behavior of monoparticulate films of nanoparticles and those of micron-size glass and latex particles.