Single-particle Brownian dynamics for characterizing the rheology of fluid Langmuir monolayers
The authors attempted to probe the rheology of fluid langmuir monolayers by tracking the diffusion of single particles at air-water interface. It is similar in spirit to the tracking of particles to study the rheology of three dimensional materials. The set-up is shown in figures 1 and 2. Polystyrene beads are interpersed in a bead of water in the presence of 3 different monolayers: N-palmitoyl-6-n-penicillanic acid (PPA), pentadecanoic acid (PDA) and L-α-dipalmitoyl- phosphatidylcholine (DPPC). The contact angle that the polystyrene beads make with the water can be measured using the set-up shown in figure 2 using the formula
where β is the water-glass contact angle.
The separation <L2>
For brownian motions of particles completely submerged in fluid, the
1. Single-particle brownian dynamics for characterizing the rheology of fluid langmuir monolayers, Sickert et al, EPL 2007