Microfibers from interpolymer complexation of κ-carrageenan and oligomers of polyaniline for glucose detection

• An interpolymer complex of polyaniline and κ-carrageenan is successfully prepared.
• The complex is micro-fibrous.
• In the complex the short rigid rod-like oligo-anilines are aligned orderly.
• The complex is of enhanced electrical and biosensing properties.

The molecular order and orientation significantly influence the physical properties of conjugated polymers and the corresponding performance in electronic devices. The precise synthesis and characterization are the challenges to obtain high quality polymer crystalline micro/nanostructures, on the basis of which, the charge transport mechanisms can be discussed and the device performance can be improved. A micro-fibrous complex of conductive polymer and natural polysaccharide has been formed during the in situ polymerization of aniline in the aqueous solution of κ-carrageenan. With the template of the polyanion, aniline is polymerized and polyaniline (PANI) chain grows in the vicinity of sulfonic acid groups. Through the comprehensive characterizations of UV–vis spectra, wide-angle X-ray diffraction, and thermal gravimetric analysis, the assembly structure of the interpolymer complex has been illuminated, i.e., oligomers of PANI with expanded conformation are formed, the electrostatic interaction between the protonated PANI oligomers and anionic κ-carrageenan makes the chains of PANI and κ-carrageenan bound together, and a micro-fibrous complex is formed with enhanced orientation of both PANI and κ-carrageenan, leading to an enhanced conductivity of the complex. The glucose biosensor made of the complex shows high detecting sensitivity and broad linear range in the recognition of the glucose due to its high conductivity and good compatibility with the enzyme.

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