AUTHOR=Golla Manohar , Cozzolino Antonietta , Nagendra Baku , Vignola Emanuele , Daniel Christophe , Rizzo Paola , Guerra Gaetano , Auriemma Finizia , D’Alterio Massimo Christian 

TITLE=Molecular Features Behind Formation of α or β Co-Crystalline and Nanoporous-Crystalline Phases of PPO

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 9 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.809850

DOI=10.3389/fchem.2021.809850

ISSN=2296-2646

ABSTRACT=Guest molecular features determining the formation of α and β phases of poly(2-6-dimethyl-1,4-phenylene) oxide (PPO) are explored by collecting literature data and adding many new film preparations, both by solution casting and by guest sorption in amorphous films. Independently of the considered preparation method, α form is favored by hydrophobic and bulky guest molecules while hydrophilic and small guest molecules favor β form. Furthermore, molecular modeling studies indicate that β form inducer guests favor more extended PPO conformations by establishing stronger dispersive interactions with the polymer chain. Thus, the achievement of CC (and derived NC) α and β forms would result from the balance between the energy gain due to host-guest interactions and the internal energy penalty of PPO chains to assume extended conformations.