DIRECT OBSERVATION OF LANGMUIR FILMS OF C-60 AND C-70 USING BREWSTER-ANGLE MICROSCOPY

The aim of this paper is to present a direct observation of Langmuir f ilms made of C-60 and C-70 along the process of their compression at 2 98 K, using Brewster angle microscopy. We found coexisting a gas phase and a condensed phase at low area densities. Om results agree with th e formation of multilayers even at low area densities (500-1000 Angstr om(2)/molecule). We made compressions of the films at several speeds. Using dilute spreading solutions (similar to 1 x 10(-5) M) and slow co mpressions we obtained multilayers. With rapid compressions, we found that the condensed phase formed beautiful foamlike structures and circ ular domains of different sizes at very low area densities. The circul ar domains developed holes (gas bubbles). As the compression of the fi lms proceeded, those domains did not coalesce easily. Instead, the fil ms prefer to form multilayers. Using concentrated spreading solutions (> 1 x 10(-4) M) and slow compressions, multilayers were formed just a fter the deposition of the sample.