Hi Dr. Wessling,

So are you suggesting that

1) in the 10 nm beads, it is metallic transport and that across the amorphous regions between adjacent beads it is hopping/tunneling?

2) the beads happen to be arranged in a bead-chain arrangement which forms the fibrillar structure of PANi?

If so my doubts are

1) how about the hopping/tunneling mechanism when the PANi well is dispersed in a media below and above the threshold concentration for self organization?

4) how about the charge transport between an aligned set of PANi chains to another aligned set of PANi chains (one domain to another domain)? Obviously charge wavefunction will experience a change in impedance when traveling from one domain to another.

Paulbert Thomas Thanks for your comment, please allow me to answer:

- I am not "suggesting" the metallic properties within the 10 nm small primary particles - it is proven, see here: Article Dispersion-induced insulator-to-metal transition in polyaniline

(and a few more papers)

- also, I am not suggesting the transport mechanism between the particles to be hopping / tunneling, also that is proven:

Article Fully protonated polyaniline: Hopping transport on a mesoscopic scale

Article Mesoscale charge transport in polyaniline

(and a few more papers)

- however, you need to know that the metallic property can only be found after the dispersion-induced drastic change of the structure within the primary particles, the structure change has been elucidated by me and published here:

Article New Insight into Organic Metal Polyaniline Morphology and Structure

- the same hopping / tunneling transport mechanism takes place also "when PAni is well dispersed", but only above a certain critical volume concentration; below this concentration, the conductivity is close to the conductivity of the (insulating) medium, at and above the critical volume concentration, the formerly well dispersed particles are forming a complex flocculated chain structure ("pearl chain") wuth the dispersion medium forming a pipe, the structure is similar to a snake having swallowed several golf balls, see the basic paper showing the structure formation above the critical volume concentration here:

Article Electrical conductivity in heterogeneous polymer systems. V ...

Hi Dr. Wessling,

Of course you have proved your points in your papers. :) What is your view on the structure of water dispersible nano fibre PANi obtained by Prof. Richard B. Kaner and team by using rapidly mixed reactants method and interfacial polymerization? The morphology of those are nano-fibres. If you take a single nano fibre, is it like the entire fibre is a metallic transport region surrounded by amorphous form? (Just like a snake which swallowed the golf stick)

thanks, I am glad to see that you digested my comments;

if you take a single nanofibre, all of them are simply pearl-chain like arrangements of primary particles; the lower the nanofibre diameter, the less primary particles are there in a cross section;

there is nothing like a "snake skin" or a "(nano) golf stick" in a PAni nanofibre, people simply did not well enough resolve the morphology of their nanofibres; EVERY conductive polymer, not only PAni, forms abour 10 nm small primary particles during polymerisation, that is because of their extremely high surface tension (look how many charged positions are on one chain = on 1 single primary particle! no chance to cope with such an extreme surface tension other than forming very small globular primary particles;

Article Frozen dissipative structures in heterogeneous polymer syste...

(to be continued: 2)

part 2

hence, as a consequence, there is no sense and no advantage in trying to make nanofibres - I made well dispersible PAni, dispersed it and let it rearrange by itself to 3-dimensional networks of pearl-chain-like fibrils; we achieved up to 1,000 S/cm, and the intrinsic conductivity within 1 partile is about 65,000 S/cm

Patent Dispersions of intrinsically conductive polymers

Article EPR study of polyaniline highly doped by p-toluenesulfonic acid

(I am still looking for a value for surface tension we had measured, as soon as I find, I will send you; I remember something but want to make sure my memory is correct)

re surface tension:

please read this here Chapter Conductive Polymers as Organic Nanometals

then you will see that the surface tension is most probably between 150 and 1,000 or 2,000 mN/m

Hi Dr. Wessling,

Sorry about the delay. So is it possible to have just the pearls without the chain in a media?

Is it possible to remove the amorphous portion of the pearl chain structure so that tunneling gets better?

Or is there a kill switch for the reaction to stop when just the metallic primary particles are produced so that the further side reactions and defects are avoided?

"haha", sorry that I am laughing, but I realized that you took my "pearl chain" analogon too exakt. Please be aware: there is no chain connecting the "pearls" to each other, the "pearls" (= PAni primary particles), they are connecting to each other forming a "chain" (without a connecting chain) just by cohesion forces;

these forces are there due to the extreme surface tension of PAni particles: at least a few hundred N/m.

Using high shear force, the metallic cores of the PAni particles can be made more conductive, and I assume, also the amorphous layer around the metallic core might become thinner (but that's an assumption so far).

Please look at the structure model and its experimental / analytical background here: Article New Insight into Organic Metal Polyaniline Morphology and Structure