Silver as a solitary atom lacks one electron in the outer orbital, and hence has a charge of +1. It can thus form compounds with entities having a net (-) charge, such as a chlorine atom. This is the ionic form, and is present in solution to various degrees when compounded with negatively charged ions or dissociated from a solid silver body by the introduction of an external electric charge. Since silver ions are monatomic, they do not reflect light and have no TE.
When generated by electric current, a mix of solid particles and silver ions streams off the surface of a silver electrode. The presence of these ions increases the conductivity of the water preparation over time, which because of the mutual ionic repulsion, reaches a plateau or saturation level.
After the external charge is removed, we have seen the conductivity of a preparation decrease over time. This may mean that two ions, by virtue of heat energy, get forced together hard enough to overcome their mutual repulsion and form a 2Ag particle, the smallest colloid. The ratio of ion to colloid in a preparation can be determined, at minimum, two ways: by measuring the TE reflectance and the conductivity. The former is operationally more complex but is preferred because it is noninvasive.
We accept that the smaller the particle size of a colloid, the higher the surface to mass ratio is,
and the more effective the preparation. We remain agnostic, however, to the wide claim that the ionic form,
being the smallest particle size, and also being electically charged, is the most active. If this is indeed the case,
how easily silver transitions back to the ionic form from the colloidal is important. We have not yet determined
in which direction or to what extent influences such as pH, elevated temperatures, cycling electromagnetic fields, etc.
drive the equilibrium.
Claims have been made that the lower the current, the smaller the particle size. However, smaller currents will
result in less material being driven off the electrodes in a given time, so it would be good to know how small
a current can be used and still produce a preparation in a reasonable amount of time.
Here is a graph detailing our findings on some different generation parameters:
The most basic is way to make Nano Ag is in a bath supplied with constant voltage between the
silver electrodes. Here we set our power supply to emulate three 9-volt batteries strapped in
series. This is suboptimal as a colloid generator, because the current, the parameter you want
to most closely control, rises with time, so presumably the size of the particle is unregulated.
Assuming fresh batteries are used, without some timing mechanism, it also requires periodic
monitoring to determine when to stop the process.
"Constant" currents of 2mA and 1mA were also tested (our evaluation unit generator has a low gain, so the
asymptotic approach to the setpoint has a slope, but no overshoot). The difference between the
1 and 2 mA starting currents is probably due to a oversight: we did not thoroughly clean out the "labware" before
starting the 2mA run, and it had residual conductivity! We will probably not re-run the 2mA, since the generation
time for the 1mA run is not much greater than the 2mA.
The time improvement using constant 1mA current versus constant voltage (over 7 hours!) to get the conductivity
to a point into the "knee" is shown below the graph. The driving current has since been lowered to 0.6mA, with little
further increase in generation time.
If in fact lower currents result in desirable low particle sizes, larger electrode surface area is desirable since
a given current divided by the emission area yields a lower current at any given point on the electrode.
In practice, we also know that electricity follows a path of least resistance. Just as water flowing downhill
tends to create channels (even without erosion) and the path of lightning through air follows a path of ionized
air molecules, the path of current in a nano silver generation bath is conducted by an ion channel.
It was thus not surprising to us to find that our skimpy 18AWG silver electrodes showed evidence of
"hot spots", places on the electrode surface that due to surface texture or location were preferred by the current.
We learned very early on to bend the wire electodes so that the ends came back out of the bath: the sharp ends of
the wires were hot spots!
We suspect that electrode design may be more important than bulk size. Lightning rods are
sharpened to provide charge jump-off points. It is quite possible that a small electrode,
pre-provisioned with emission multiple points and an engineered topology, may outperform a
larger, "flat" electrode.
Claims have been made that reversing the polarity periodically keeps electrodes clean so they
do not have to be buffed with a scrubbie between runs. We have generally found this to be the
case. However, early observations indicate the switching time period, like stirring, can have a profound impact on
conductivity, so we will be doing further work to determine the optimum switching time.
Our present swiching time of about 8 minutes is probably long enough to minimize this effect, however.
We are currently agnostic regarding the need to stir the bath, which some
others claim as
essential. However, we have taken data in unstirred, 4 seconds on / 4 seconds off vigorously stirred and gently
stirred preparations (generator current set to limit at 0.6mA) that are summarized in this graph:
What is immediately obvious is that stirring greatly increases the impedance of the bath.
Presumably the continuity of a path of ions promotes conductivity, and stirring, much the way
wind disrupts a bolt of lightning, breaks up this channel. What is not immediately
obvious is whether or not stirring produces a smaller particle size of nano ag, or increases the
ion to particle ratio. We will not be able to determine this until we can quantify the sauce with optical reflectometry.
That the impedance of
the bath quickly rose to a higher level than distilled water is strange enough, but even stranger, the voltage
output of our evaluation generator rises only to 63V or so when the output is left completely open.
Fortunately, gentle stirring the bath results in conductivity increases similar to unstirred runs. You can see by
the curve that there is a slight starting increase in resistance, but it is not as drastic as when vigorously stirred.
Analyzing the results from optical reflectometry should give some insight into the preparation quality.
STRANGE FINDING: In the vigorously stirred run the calculated impedance of the bath rose quickly to
over 3 million ohms, driving the output voltage of our
evaluation generator to 80V, at which level it risked
self-destruction. We stopped the run, inserted a 274Kohm resistor in parallel with the bath, and re-started it.
That impedance was later back-calculated out to derive the bath resistance for the graph above.