Inclusion complexes of poly(4-vinylpyridine)-dodecylbenezenesulfonic acid complex and cyclodextrins

Abstract

P4VPy(DBSA)x complexes (x = 0.25, 0.50, 0.75, or 1.00 DBSA/P4VPy repeat units) are able to form inclusion complexes with three cyclodextrins (CDs). The complexes were characterized by XRD, XPS, 13C CP/MAS NMR, 1H NMR, DSC, and TGA. A columnar structure with poor order is established in all the inclusion complexes. XPS studies show that the interaction between DBSA and P4VPy is affected by inclusion complexation when the DBSA content is high (x ≥ 0.5), resulting in the expulsion of some DBSA ions from the polymer chain and reprotonation. TGA shows that the initial decomposition temperatures of the inclusion complexes are lower than those of the CDs and the pristine complexes, a result different from that of the linear chain polymer-cyclodextrin ICs. DSC measurements indicate that the inclusion of the side chains within CDs makes the P4VPy main chain much stiffer, thereby raising the glass transition temperature. 1H NMR measurements also suggest that interactions between CDs and the side chains of P4VPy(DBSA)x complexes are present even in DMSO solution. However, the mesomorphic layer structures of P4VPy(DBSA)x complexes are destroyed upon the formation of inclusion complexes with CDs.