Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/92970
Title: A new water-soluble, self-doping conducting polyaniline from poly(o-aminobenzylphosphonic acid) and its sodium salts: Synthesis and characterization
Authors: Chan, H.S.O. 
Ho, P.K.H. 
Ng, S.C. 
Tan, B.T.G. 
Tan, K.L. 
Issue Date: 23-Aug-1995
Source: Chan, H.S.O.,Ho, P.K.H.,Ng, S.C.,Tan, B.T.G.,Tan, K.L. (1995-08-23). A new water-soluble, self-doping conducting polyaniline from poly(o-aminobenzylphosphonic acid) and its sodium salts: Synthesis and characterization. Journal of the American Chemical Society 117 (33) : 8517-8523. ScholarBank@NUS Repository.
Abstract: Poly(o-aminobenzylphosphonic acid) and its sodium salts, made by progressive neutralization with NaOH, have been prepared and characterized. Both the hemisodium and monosodium salts are intrinsically self-doped and water-soluble in the conducting form. The key is to control the ionization of the excess acid functions on the polymer chains. XPS results suggest that the polymer is obtained directly in the 43% polyzwitterionic (i.e., self-doped) emeraldine form. The self-doped polymer does not exhibit any conductivity dependence on pH below 6, in marked contrast to the HCl-doped polyanilines. Our structurally well-defined polymer system displays only one set of redox activity over the potential range of -0.2 to 1.2 eV, alluding to the higher stability of the self-doped structure. This is unique and different from other polyaniline systems which show two sets of redox peaks. FTIR spectroscopy provides evidence for strong intra-chain hydrogen bonding while NMR studies conclude that protonated and unprotonated segments of the solvated monosodium polymer are distinct. The lower conductivity (∼10-3 S cm-1) obtained is attributed to the decrease in conjugation caused by the large steric effect of the bulky PO3H2 and a significant hydrogen bond interaction between PO2(OH)- and NH·+ leading to significant charge-pinning. UV-vis data can be explained by a increased participation of the nitrogen wave function in the HOMO, and thereby the widening of the πB → πS band gap.
Source Title: Journal of the American Chemical Society
URI: http://scholarbank.nus.edu.sg/handle/10635/92970
ISSN: 00027863
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

Page view(s)

51
checked on Feb 15, 2018

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.