Influence of �?-cyclodextrin as an encapsule and as an inclusion complex dopant on conducting polyaniline

[摘要] An investigation on the effect of ð›�?-cyclodextrin (CD) in both free and inclusion-complexed forms with a guest anionic metal complex, dioxalatodiaquochromate(III) (DDC), on the characteristics of conducting 2â€�?�polyaniline (PANI) is carried out. Four materials, PANI (i.e. PANIâ€�?�SO₄), PANIâ€�?�DDC, PANIâ€�?�CD and PANIâ€�?�CD + DDC were prepared by in situ chemical oxidative polymerization in aqueous H₂SO₄ at pH 1 and subjected to electrical conductivity and spectral (IR and UV-vis) measurements. DDC and CD when separately incorporated, reduce the conductivity of PANI by about half whilst their inclusion complex CD + DDC enhances it. Spectral characterization reveals that DDC as a dopant and CD as an encapsule exhibit their effects through adverse interaction with imineâ€�?�amine N centres and benzenoid moiety of PANI. The inclusion complex CD + DDC, on the contrary, functions as a dopant by lying in between the chains and seems to promote the extended conformation of PANI chain and hence the ðœ�?-electron delocalization. Exposure of the material to methanol vapour causes a decrease in conductivity in PANI and PANIâ€�?�CD while an increase in PANIâ€�?�CD + DDC. This study makes explicit the distinct role of CD as an encapsule and CD + DDC inclusion complex as a dopant in altering the electrical property of PANI.

[学科分类] 材料工程

[关键词] ð›�?-cyclodextrin;dioxalatodiaquochromate(III);inclusion complex;characteristics development.