THERMAL-EXPANSION AND COMPRESSIBILITY IN CHAIN DIRECTION OF A POLYDIACETYLENE SINGLE-CRYSTAL

In reported experiments, an x-ray back-reflection rotating camera has been used to measure the lattice constant, thermal expansion, and compressibility in the polymer chain direction of a polydiacetylene, poly left bracket bis(p-toluene sulfonate) of 2,4-hexadiyne 1,6-diol right bracket . The thermal expansion coefficient of the polymer chain is small and positive (0. 9 plus or minus 0. 2 multiplied by 10** minus **6 degree K** minus **1) at 300 K, but negative below about 70 K. Application of 3. 43 kbar hydrostatic pressure at 299 K changed the unit cell dimension in the polymer chain direction by less than 10 ppm.