Colloidal Science Laboratory, Inc.

About CSL

CSL was formed to conduct research and development in the field of metal colloids. The lab is primarily involved in two fields of scientific investigation pertaining to colloids: process development and analytical measurements to determine their physical properties.

Staff Scientists

The laboratory was founded by Francis Key, who serves as the Principal Scientist. Educated at Columbia University and Newark College of Engineering, he has an extensive background in the fields of electrical engineering, computer science, and various branches of physics and engineering. Mr. Key's experience in scientific research and engineering spans a period over 35 years, beginning with his contributions to the design of space flight hardware used on the Apollo and Viking space missions. Mr. Key is known for meticulous attention to details, and relentless investigative procedures, which have led to innovative solutions in defense, aerospace and private industry. Mr. Key has carefully researched the production of colloidal silver, and has built a state-of-the-art laboratory facility for colloidal research. He has also instituted analytical methods and developed manufacturing processes that ensure the highest purity and consistency possible for a colloidal product.

Dr. George Maass serves a senior scientific advisor to CSI. He holds degrees in chemistry from Fordham University and Iowa State University. For the last 6 years, Dr. Maass has been a professor of chemistry at Camden County College, while operating his own consulting business. He has authored papers and presented seminars on his work in the US, England and Mexico.

Process Development

Research has focused on developing processes to produce colloids with superior physical properties using techniques heretofore unknown in the industry. Process development has involved the use of advanced scientific principles in physics, chemistry and quantum mechanics.

CSL processes have been developed with the emphasis on the continuous production model rather than the more typical batch process model. Many electrochemical techniques used to produce metal colloids are batch processes which means that the product is produced in batches of a fixed amount, for example, 10 gallons.

CSL has succeeded in developing proprietary processes that produce metal colloids whose particle size is dramatically smaller than any known to exist previously. The mesoprocess developed at CSL simultaneously produces very small particles and a high percentage of particles vs ions. Particle size is especially important because the resulting increase in particle surface area promotes a higher reaction potential with the metal particles which directly relates to effectiveness.

CSL pioneered in the development of low ionic/high particulate silver colloids by producing colloids that are nearly devoid of ionic content. The high quantity of particles combined with their small size provides the most desired combination of properties. This set of properties produces the highest particle surface area for a given concentration.

Analytical capabilities

In order to perfect the new production processes, the laboratory must be able to quantify the physical properties that have been determined to be important to the quality and effectiveness of the colloids.

One of the most important properties of a colloid and one of most difficult to properly measure is the size distribution of the particles. We researched particle size measurement technology as it applies to nanometer sized particles and chose a state-of-the-art Photon Correlation Spectrometer (PCS) produced by one of the worlds leaders in the field of particle characterization. The PCS provides accurate and repeatable measurements of the particles size distribution of the colloidal particles over a range from less than a nanometer up to 3000 nanometers. The PCS also measures Zeta Potential, a property important to understanding colloid stability and surfactant chemistry. The PCS is an essential analytical tool that produces data essential to understanding the process factors that affect particle size.

CSL pioneered in the development of techniques to accurately measure the ionic content of colloids by separating the particles from the ions using Ultra centrifugation that produces up to 360,000 G forces for separating the smallest particles from the ions. Once separated, the ions can be measured using Atomic Absorption Spectroscopy. Accurate measurement of ionic content is essential to properly evaluate the process variables that affect the ion/particle ratio. Such process variables are optimized to maximize the particles and minimize the ionic content of the colloids.

Other relevant properties of colloids include conductivity, turbidity, pH, and concentration.

The lab is equipped to perform measurements of all the physical properties of metal colloidal solutions that pertain to the quality and effectiveness of the product. All measurements use standards traceable to N.I.S.T. and are performed by professional personnel with extensive experience in the laboratory procedures and equipment used to make the measurements.

Laboratory Capabilities

The laboratory analytical capabilities are focused on measuring the physical properties of colloids. The physical properties that we measure are those that relate to the quality and effectiveness of colloidal solutions.

The properties of interest are:

• Concentration (ppm) of ions
• Concentration (ppm) of particles
• Conductivity
• Particle size distribution
• pH
• Turbidity
• Zeta potential

From these measurements we calculate particle surface area which directly relates to effectiveness and serves as a metric for comparison with other colloids. The equipment listed below comprises the scientific equipment used by the laboratory personnel to determine the physical properties described above.

Atomic Absorption Spectroscopy (AAS) - A Perkin-Elmer Model 4100 Flame AAS with deuterium background correction is used to determine concentration of trace metals in sample solutions. The AAS is currently equipped to measure silver, gold, copper, iron, and titanium. The AAS is used to determine total silver in silver colloids. Ionic silver content in silver colloids is determined by first removing the particles by centrifugation and then measuring the silver content remaining in the solution.

Analytical Balance - An A&D Model HM-202 balance reads grams to five decimal places (10 microgram resolution) and is used for general lab work and preparing dilutions by weight (mass).

Centrifugation - The lab has several centrifuges with the capacity to provide a wide range of separation functions from continuous flow processing to ultra G-force separation.

Continuous flow - A Carr Separation Powerfuge Pilot with an axial bowl produces variable G-forces from 50 - 20,000 G's while processing flow rates up to 4 liters per minute.

Ultra G-force - Beckman L8-80M Ultra Centrifuge is a microprocessor-controlled ultracentrifuge used to generate centrifugal forces up to 365,000 Gs for particle separation. Maximum of 80,000 rpm is produced by this unit with total rotor volume of 150 mL in a refrigerated vacuum chamber.

High capacity - A Hermle ZK-364 Centrifuge with swing bucket rotor provides a total rotor capacity of 720 mL and 4500 G-forces in a refrigerated chamber.

Conductivity - Conductivity Meters: Hanna Instruments HI 8733 Conductivity Meter, HI 9033 Multi-range Conductivity Meter and Ultra Pure Water tester (UPW).

Evaporation/Concentration - A Buchi Rotavapor Model 124 with Buchi digital vacuum controller and Lauda IC-30 immersion cooler comprise the evaporator system that is used in general laboratory tasks involving evaporation and concentration of solutions.

Particle Size Characterization - Malvern Zetasizer 3000HSA In the Zetasizer, the particle size of colloidal particles is measured using laser light scattering and the technique of photon correlation spectroscopy (PCS). With this technique the fluctuations in the intensity of light scattered by colloidal particles are analyzed using a digital correlator to determine the diffusion coefficient and size distribution of the particles.

pH/ISE - Orion 710A with an ion specific electrode for silver is used to make ISE silver measurements. A pH probe is used for both high and low ionic pH measurements.

Turbidity - Turbidity Meter: Orbeco-Hellige Digital Direct Reading Turbidity Meter, Model 965 measures turbidity in three ranges (20, 200, and 1000 NTU).

Zeta Potential - Malvern Zetasizer 3000HSA measures zeta potential. Zeta potential is a measure of the magnitude of the repulsion or attraction between particles in a colloid. Its measurement brings detailed insight into the dispersion mechanism and is the key to electrostatic dispersion control.