Transcript The effect of Rf-irradiation on ECD –A manifestation of induced long range order? (1)(2)(*)($) Y.Katsir , (3)(*) L.Miller , (1) Y.Aharonov , (1) E.Ben-Jacob The protocol The effects of RF-irradiation of water 1.

The effect of Rf-irradiation on ECD –A manifestation of induced long range order?
(1)(2)(*)($)
Y.Katsir
,
(3)(*)
L.Miller
,
(1)
Y.Aharonov ,
(1)
E.Ben-Jacob
The protocol
The effects of RF-irradiation of water
1. We performed ECD experiments in control solutions, solutions that where treated by RF-irradiation
before the ECD process and in solutions made from NPD-water.
2. We monitored the pattern on the macro-scale and used HR SEM and SEM to study the micron-level
organization of the deposits.
3. The RF-irradiation was at 915 MHZ , for about 20 minutes and about 10W power while keeping the
water at fixed temperature.
During the past two decades, much effort has been devoted to study the long term (hours)
effects of rf-treatment on the properties of water and aqueous solutions (1-3). The following are
some examples of well documented effects: 1. Formation of stable gas nanobubbles.
2. A decrease in surface tension from 72 to 68 dyn/cm. 3. Increase in the intensity of all three
infra-red (IR) spectroscopy frequency bands. 4. Increase in the concentration of atomic
hydrogen. 5. Modifications in the spectra of dissolved hydrophobic fluorescent molecules.
6. Changes in the zeta potential.
It was proposed that the effects are due to water ordering induced by the gas bubbles. Here we test
this hypothesis by study of the effect of RF-treatment on Electro-Chemical-Deposition (ECD) (1).
The experimental findings
Rf-treated solutes
Control
NPD-water
Electro-Chemical-Deposition in Circular Cells
ECD of metals in thin gap geometry has been widely used over the last twenty years to
study the foundation of pattern formation and self organization in open systems far
from equilibrium. A great variety of macroscopic patterns (morphologies) are formed
as a function of several control parameters: applied voltage, initial concentration,
chemical composition of the solutions, its viscosity etc.
The typical Morphology Diagram
The circular ECD cell
DBM
Induced Morphology Diagram: For some growth conditions that dendrites are grown in
the control solution, DBM morphology is generated in the RF-treated solutions and in the
solutions made from NPD-water.
Dendrites
Micro-Macro interplay and Morphology Selection in ECD:
Measurements on all scales from micro-level structures (using electron microscopy and
X-rays) to the macro-level patterns played a crucial role in establishing the theoretical
framework about the micro-macro singular interplay reflected in the morphology
selection and morphology transitions. In this regard the ECD process provides a probe
of micro-level effects.
50µm
50µm
SEM observations of the effect on the DBM: These results are at lower voltages (8V).
Nano Particle Doped water (NPD-water)
HR SEM
TEM
Sub-micron
hot
(900)
source powder is dropped
into RF-irradiated water
kept below the anomaly
temperature. The process
leads to the formation of
spherical particles
Source powder
The NPD-water used here is the Neowater (5)
that has about 1012 particles per 1ml
The effect on Dendritic growth: These results are at higher voltages (13V).
Nanobubbles stability –
Experimental proof using AFM
The New paradigm
We propose that our findings together with the previously reported anomalous effects
of RF-treatment hint the existence of new physical phenomenon – The formation of
Nanobubble Networks
The processed particles
Bubble-Bubble
Exchange Interactions
It has been proposed before that
We propose that:
(1) The nanobubbles have long-term
stability (hours);
1. The induced order around
each of the nanobubbles
mediates bubble-bubble
exchange interactions.
(2) The gas-water interface of the
nanobubbles is hydrophobic and
therefore the water molecules form
clathrate shells with an “ice-like”
structure around the gas
nanobubbles;
Direct
observations
of
nanobubbles
on
hydrophobic surfaces using liquid atomic force
microscopy in high resolution tapping mode (4).
The observations revealed that once formed, the
nanobubbles can be stable for hours. (Picture is
thanks to P. Attard ref(4 ))
Nanobubbles
3. The networks induce long
range order.
4. In NPD-water nanoparticles act
as the hubs leading to
stabilization of the nanobubble
networks.
As a step in this direction, we used Isothermal Titration Calorimetry (ITC) to test the effect of injecting
solutions made with the NPD-water into control solutions and vice versa. The preliminary results show an
endothermic peak in the former case, implying that the NPD-water solutions have lower free energy, which is
consistent with the hypothesis about induced long range order (1).
Subtraction of
ZN in NPD -> ZN in NPD
Microcal/sec
Microcal/sec
Subtraction of ZN -> ZN
sec
Particle
Nanobubbles
Affiliations
Testing the New paradigm
Microcal/sec
2. The exchange interactions lead
to the formation of nanobubble
networks with hierarchical
organization. With larger bubbles
being the hubs of the network.
The effect of
Nano particle doping
Bubble
(3) The ordered shells can induce
order in the water molecules
surrounding the nanobubbles that
extends up to a micron in range.
sec
Formation of
Nanobubble Networks
sec
(1)School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel (2)
Current address: Department of Chemistry Bar Ilan University, Ramat Gan 52900,
Israel
(3) Department of Materials Engineering, Technion, Haifa 3200, Israel
(*) These authors have equal contributions
($) Presenting author
References
(1) Y. Katsir*, L. Miller*, Y. Aharonov and E. Ben-Jacob, The effect of rf-irradiation on
electrochemical deposition and its stabilization by nanoparticle doping J.
Electrochemical Society (accepted 2007). (*) these authors have equal contributions.
(2) For definition of water formatics see “Exploring water complexity” in:
http://star.tau.ac.il/~eshel/
(3) M. Colic and D. Morse, Physical Review Letters, 80, 2465 (1998)
(4) P. Attard, Advanced in Colloid and Interface Science, 104, 75 (2003).
(5) The NPD-water is NeowaterTM provided by Do-coop Technologies Ltd.