S. Arisawa et al., STRUCTURAL INVESTIGATION OF ALTERNATING LANGMUIR-BLODGETT-FILMS OF AMPHIPHILIC DIACETYLENE AND FATTY-ACID, Thin solid films, 242(1-2), 1994, pp. 295-299
Heterostructured Langmuir-Blodgett films of stearic acid (C18) and unp
olymerized pentacosadi-10,12-ynoic acid (CH3(CH2)IIC=C-C=C(CH2)8COOH)
were prepared and the structures of unpolymerized and photopolymerized
films were investigated by X-ray diffraction. The structural changes
caused by photopolymerization were discussed. The order of deposition
was varied systematically. It is found that the interplanar spacings a
nd molecular alignments of the heterostructured films strongly depend
on the order of deposition. For the three and four-layer cyclic films,
a ''partially overturned'' structure was observed in some unpolymeriz
ed films, which means that some molecules become Z or X films from Y t
ype. Moreover, polymerized films returned to a Y-type structure. From
the films with rather thick periodicity as long as about 200 angstrom,
satellite reflections were observed suggesting that high stacking ord
er can be achieved over large distances and the macroscopic molecular
orientations are highly ordered in spite of the microscopic inhomogene
ity.