Molecular Engineering of Polyphosphazenes and SWNT Hybrids with Potential Applications as Electronic Materials

Polymer/single-walled carbon nanotube (SWNT) hybrids are promising candidates in applications such as flexible and stretchable electronics. In this contribution, we have examined structure-property relationships for constructing new polyphosphazene-SWNT hybrids. UV-vis and Raman spectroscopy studies revealed that the unique P=N backbone enables strong intermolecular donor-acceptor interactions between the polymer and SNWTs. Furthermore, the polymeric backbone and the environment at the P-centers collectively play important roles in the formation of the hybrids. For polymers with shorter alkoxy substituents, the donor-acceptor interactions between the P=N backbone and SWNTs play a crucial role in stabilizing the hybrid complexes, but for polymers with longer alkoxy substituents, the CH-π interactions and steric hindrance between the alkyl side chains and SWNTs counterbalance each other and control the stability of the hybrid complexes. Furthermore, the presence of fluorine and oxygen atoms is detrimental to the stability of the hybrid complexes. New cross-linkable polyphosphazenes with anthracene side units were also synthesized. When photo-cross-linked, these polyphosphazene/SWNT hybrids showed elastomeric characteristics and electronic properties that are promising for future applications.