Melting of nanoporous-crystalline and co-crystalline solution cast films of poly(2,6-dimethyl-1,4-phenylene) oxide

The melting behavior of nanoporous-crystalline (NC) and co-crystalline (CC) PPO films is mainly studied by differential scanning calorimetry. For NC films, the dependence of melting behavior on alpha or beta forms as well as on the chemical nature of the guest of precursor CC forms is explored. A relevant result of this contribution is that the use of PPO films with c(//)orientation also allows establishing melting temperatures of CC phases, being not accessible for other PPO samples. An additional relevant result is the achievement, by suitable annealing procedures on c(//)oriented CC films, of partially filled CC PPO films with melting temperature just below 300 degrees C, while NC PPO films always exhibit melting temperatures lower than 265 degrees C. The reported data, both on NC and CC films, also indicate that molecular volumes most suitable for guests of the alpha NC form of PPO are in the range 160-230 angstrom(3).

Automated summary

This study focuses on the melting behavior of nanoporous-crystalline (NC) and co-crystalline (CC) PPO films using differential scanning calorimetry. Results reveal that PPO films with c(//) orientation help establish melting temperatures of CC phases and achieve partially filled CC PPO films with lower melting temperatures through annealing. Molecular volumes suitable for guests of the alpha NC form of PPO are found to be in the range of 160-230 angstrom(3).