How hydrochloric acid as a dopant in polymeric chains of polyaniline enhance the thermal stability ?
Anil,
your Question is not supply the enough information, therefore, I am unable to provide the exact answer you want. But polyaniline we called emeraldine base (Blue) convert to the emeraldine salt( Dark green colour) which as higher conductivity. Its increase the conductivity because of chain reaction via polarons and positrons (you can search it in Google, there are many articles). But practically as my experience, when we supply heat above the 110 centigrades the conductivity getting decrease because of the polymeric structure getting to damage( change)
Hope this will help you !
Anil, Emeraldine Base is extremely stable, > 400°C. Using HCl as doping is the worst option - thermally most unstable (even less than 110°). HCl evaporates and moreover, when neutralizing (removing HCl using bases), you will always find Cl in elemental analyses = HCl has chlorinated the chain somewhere.
Exactly, Prof. Wessling, HCl is generally chlorinated the chain.
If we see other aspect, with doping process the flow of electronic cloud in the backbone of polymeric chains is also increased which may due to the formation of smooth path in the chains. The generation of new path should be due to some kind of interaction or bonding. If this is true, Can it affect the thermal stability ?
a) the electron flow is not (at least not primarily) along the chain backbone, but 3-dimensionally within the primary particles and (by hopping) from particle to particle, please read this
https://www.researchgate.net/publication/49593603_New_Insight_into_Organic_Metal_Polyaniline_Morphology_and_Structure?ev=prf_high
and literature cited therein.
b) eletron flow is not enhanced due to formation of "paths" but due to generation of more or less metallic 3D electron bands (less metallic in case of inhomogeneous doping)
c) the thermal stability of "doped" PAni types (HCl or compared to this other acids) is mainly due to thermal diffusion of the acid and evaporation
Article New Insight into Organic Metal Polyaniline Morphology and Structure
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials Chemistry