  Molecular aggregation and monolayer characteristics of non-amphiphilic
p-terphenyl (TP) mixed with either polymethyl methacrylate (PMMA) or stearic
acid (SA) at the air-water interface were investigated. The miscibility of the
two components was evaluated by measuring and analyzing surface pressure versus
area per molecule (pi-A) isotherm. Both attractive and repulsive interactions
between the sample (TP) and the matrix (PMMA or SA) were observed depending on
the composition and microenvironment. TP and PMMA/SA were not completely
miscible in the mixed monolayer. Aggregation and phase separation between
sample TP and matrix molecule was revealed by UV-Vis absorption spectroscopic
studies and confirmed by scanning electron micrograpgh of LB films.
