Optical trapping of particles at the air/water interface for studies in Langmuir monolayers

Abstract

Optical experimental devices allow to observe and manipulate several micron-sized objects, for instance, condensed phase domains formed in Langmuir monolayers at the air/water interface. In this paper, an experimental instrument designed to trap and manipulate those domains is presented. This instrument consists of optical tweezers, colloidal beads as handles and Brewster angle microscopy (BAM) to observe the trapped domains. With this instrument it was possible to trap and observe small domains ($20-30 \; \mu$m) of nervonic acid monolayers.