Melting, crystallization, and solution behavior of chain molecules with hydrocarbon and fluorocarbon segments

Melting, crystallization, and solution behavior of n ‐alkanes with fluorocarbon segments of twelve carbon atoms on one end, F(CF 2 ) 12 (CH 2 ) n H, or on both ends, F(CF 2 ) 12 (CH 2 ) n (CF 2 ) 12 F were investigated by DSC, MAS 13 C NMR, light scattering, and birefringence studies. Both triblock F(CF 2 ) m (CH 2 ) n (CF 2 ) m F and diblock F(CF 2 ) 12 (CH 2 ) n H compounds with 4 ≦ n ≦ 14 melt by a two‐step process. In the first step, the alkyl segment conformations gain nearly liquid like trans/ gauche ratios, while the perfluorinated segments remain ordered. “Gels” which incorporate the entire solvent are formed by crystallization from even dilute solutions of hydrocarbon and fluorocarbon solvents. The gels are built up of extremely long, interdigitated needles of the pure solute. Due to the bilayer structures and different degrees of ordering of the hydrocarbon and the fluorocarbon segments, the crystals grow preferentially in the direction parallel to the lamellar surface. Light scattering experiments in octane demonstrated the formation of micelle type associates.