Improved mechanical and electronic properties of co-assembled folic acid gel with aniline and polyaniline.
Co-assembled folic acid (F) gel with aniline (ANI) (ANI:F = 1:2, w/w) is produced at 2% (w/v) concentration in water/DMSO (1:1, v/v) mixture. The gel is rigid and on polymerization of the gel pieces in aqueous ammonium persulfate solution co-assembled folic acid - polyaniline (F-PANI) gel is formed. Both the co-assembled F-ANI and F-PANI gels have fibrillar network morphology, the fiber diameter and its degree of branching increase significantly from those of F gel. WAXS pattern indicates co-assembled structure with the F fiber at the core and ANI/PANI at its outer surface and the co-assembly is occurring in both F-ANI and F-PANI systems through noncovalent interaction of H-bonding and π stacking processes between the components. FTIR and UV-vis spectra characterize the doped PANI formation and the MALDI mass spectrometry indicates the degree of polymerization of polyaniline in the range 24-653. The rheological experiments support the signature of gel formation in the co-assembled state and the storage (G') and loss (G″) modulii increase in the order F gel< F-ANI gel < F-PANI gel, showing the highest increase in G' ≈ 1100% for the F-PANI gel. The stress at break, elasticity, and stiffness also increase in the same order. The dc-conductivity of F-ANI and F-PANI xerogels is 2 and 7 orders higher than that of F xerogel. Besides, the current (I)-voltage (V) curves indicate that the F-xerogel is insulator, but F-ANI xerogel is semiconductor showing both electronic memory and rectification; on the other hand, the F-PANI xerogel exhibits a negative differential resistance (NDR) property with a NDR ratio of 3.0.
Polymer Science Unit, Indian Association for the Cultivation of Science , Jadavpur, Kolkata 700032, India.
Priyadarshi
P
Chakraborty
Partha
P
Bairi
Bappaditya
B
Roy
Arun K
AK
Nandi
D000814:Aniline Compounds / Q000737:chemistry*; D004548:Elasticity; D005492:Folic Acid / Q000737:chemistry*; D005782:Gels / Q000138:chemical synthesis / Q000737:chemistry*; D008422:Materials Testing; D010316:Particle Size; D013499:Surface Properties
D000814:Aniline Compounds; D005782:Gels; C416807:polyaniline; D005492:Folic Acid; C023650:aniline