Temperature dependence of the thickness of Langmuir multilayer assembly films

The thickness of Langmuir films was examined for temperatures ranging from - 193 up to 80°C by using x-ray diffraction. Up to around -40°C, the thickness remains almost constant or the thermal expansion coefficient $\alpha \sim 1\times {10}^{-5\mathrm{}}$ ${\mathrm{deg}}^{-1\mathrm{}}$. Beyond -20°C, the thickness tends to decrease; $\alpha <0\mathrm{}$ and $\left|\alpha \right|$ increases with temperature.