Applications of Sonication/Ultrasonic Processing in Nanotechnology

By AZoNano.com Staff Writers

Topics Covered

Introduction
Probe Diameter and Sample Volume
Probe Sonicator
Solid Tip Probes
Probe Sonicators vs. Ultrasonic Cleaner Baths
Viscosity and Temperature
Conclusion
About Qsonica

Introduction

Ultrasonic processors are being increasingly used for deagglomerating and dispersing nanoparticles. Probe sonication is suitable for producing dispersions, which can remain in suspension for a number of months. Qsonica, who has years of experience in working with clients in the nanotech industry, offers the following information on dispersing and deagglomerating nanoparticles.

Probe Diameter and Sample Volume

First, the diameter of the probe must match with sample volume. For instance, a sonicator system comes with a ½” diameter probe, which can be used for samples up to 250 ml. A larger probe is required for larger samples.

For instance, using the ½” probe for processing larger volumes may take a long time and also may not sufficiently disperse the samples. In one instance, a customer used a ½” probe to process a 1,000 ml sample which took more than an hour to obtain the desired results.

Moreover, by running the system for extended period of time the samples were overheated. The customer then switched to a 1” probe with a booster and was able to reduce the processing time by 50%. A high gain horn will deliver the same high output as a booster/horn combination.

Probe sonicator from Qsonica

Probe Sonicator

Users can process large sample volumes in a continuous flow. If a probe sonicator is used to disperse the sample in a beaker, it can be upgraded to larger volumes with a Flocell inline processing device.

Solid Tip Probes

A solid tip probe must be used with low surface tension liquids or organic solvents. Standard probes with ½”, ¾” and 1” diameters feature small, replaceable tips at the end. Solvents tend to enter into this connection point, irrespective of the tightness of the tip. When this occurs, the sonicator will not perform effectively and the system may overload or produce an error message.

Flocell inline processing device

Probe Sonicators vs. Ultrasonic Cleaner Baths

When compared to ultrasonic cleaner baths, probe sonicators are more effective and powerful. A probe sonicator will do the task in minutes, while a cleaner bath will take hours to accomplish the same job. This is explained in detail in the following article excerpt:

"Dispersions in vial (a) have coagulated CNTs in the body and at the base with bath sonication for 8 hrs; dispersions in vial (b) show free-homogenous by means of probe sonication for 3 minutes; and dispersions in vial (c) appear free-homogenous even after four months of sitting at room temperature. The MWCNTs/SDS ratio is 1:10 and the concentration of MWCNTs is 2500 mg/L. Using deionized water, (d) MWCNTs of (c) was diluted to 25 mg/L.

"It is obvious that MWCNTs are not entirely dispersed in water with bath sonication for 8 hrs. Large amount of MWCNTs sedimentation can be seen at the base of vial (a). After applying a 20 kHz with a probe sonicator, the MWCNTs were able to disperse in the aqueous solution, creating a homogeneous-free solution as shown in vial (b). Surprisingly, sedimentation was not seen even after four months of sitting at room temperature, as shown in vial (c)."

Figure 1. Solubility of MWCNTs in aqueous solution

Viscosity and Temperature

Viscosity and temperature are the two main issues that need to be considered. A probe system can function within a sample temperature of 100°C. The heat can pass up the probe to the converter and cause overheating and overload conditions. In case the temperature of the sample is close to this value, the converter should be air cooled. The maximum viscosity that can be processed is about 4000 cps. Air cooled converters are available and can be joined to conventional compressed air systems.

Conclusion

Probe sonication can be effectively used to form dispersions, which can remain in suspension even after several months. Qsonica help customers in choosing the right sonicator for their specific applications.

About Qsonica

Qsonica designs, develops and manufactures the world's most technologically advanced ultrasonic liquid processors. Our 40 years of experience in a wide range of industries has enabled us to develop a full line of equipment and accessories to provide solutions for the following applications:

  • Cell Disruption
  • Nanoparticle Dispersion
  • Creating Emulsions
  • Shearing DNA
  • ChIP Assay
  • Homogenization

This information has been sourced, reviewed and adapted from materials provided by Qsonica - Ultrasonic Liquid Processors.

For more information on this source, please visit Qsonica - Ultrasonic Liquid Processors.

Date Added: Jul 19, 2013 | Updated: Jul 22, 2013
Ask A Question

Do you have a question you'd like to ask regarding this article?

Leave your feedback
Submit