Oil-in-Water Emulsions
In oil-in-water emulsions, the oily phase is mixed into the aqueous phase. Ultrasonic emulsifiers are ideal for creating these emulsions, offering uniform droplet dispersion and long-term stability, making them popular in labs and production.
Benefits of Hielscher Sonicators for Oil-in-Water Emulsions
- Uniform, stable, nano-sized emulsions
- Repeatable and reproducible results
- Perfectly scalable from lab to production
- Expert support from Hielscher technical team
Use Hielscher for Your Emulsion Project
Hielscher Ultrasonics provides advanced sonicators and extensive support to help you create uniform, stable oil-in-water emulsions with nano-sized droplets. Our technical lab can perform tests and measure nano-size emulsions. Improve your products with our ultrasonic equipment and expertise. Complete the inquiry form to learn more.
Tell us about your emulsion formulation. Our sonication expert will recommend you the ideal sonicator configuration and assist you with tipps.
Ultrasonic Oil-in-Water Emulsions
Oil-in-water (O/W) emulsions are widely used in consumer products such as food, beverages, cosmetics, and pharmaceuticals, as well as in industry (e.g., material science, polymers, paints, coatings, fine chemistry).
Definition of Oil-in-Water Emulsion
An oil-in-water emulsion is a mixture where small droplets of oil are finely dispersed in water or another aqueous liquid. The quality of oil-in-water emulsions depends on the formulation (oil-to-water ratio, emulsifying agent) and the emulsification technique. Hielscher ultrasonic emulsifiers utilize acoustic cavitation, generating intense high-shear forces and turbulence to break the immiscible liquids into very small droplets and mix them uniformly. This method can produce nano-sized particles as small as 10 nm, offering very small, uniform droplet sizes and making sonication the preferred emulsification technique.
Nano-Emulsification with the UP400St Sonicator
Benefits of Ultrasonic Emulsification
Ultrasonic emulsification outperforms other techniques like high-pressure homogenization and high-shear mixing by offering efficient, consistent production of nano-droplets and high emulsion stability. Studies show that ultrasonic emulsification produces more uniform and stable emulsions compared to other methods, with significantly longer stability periods.
The curve shows the nano-scale droplet distribution of an ultrasonically dispersed nano-emulsion. This ultrasonic emulsion consists of oil emulsified into a continuous water phase.
Advantages of Ultrasonic Emulsions
- Highly efficient process
- Produces sub-micron and nano-droplets
- Ensures uniform droplet size distribution
- Delivers reproducible results
- Suitable for any volume
- Precisely controllable
- Linearly scalable
- Safe and easy to operate
Ultrasonic preparation of an oil-in-water (O/W) emulsion (red water / yellow oil). A few seconds of sonication turn the separate water/oil phases into a fine emulsion.
The Working Principle of Ultrasonic Emulsification
Ultrasonic emulsification relies on acoustic cavitation, generated by high-intensity, low-frequency ultrasound (16-30kHz). This energy, transmitted via an ultrasonic probe, creates high-pressure and low-pressure cycles, forming and violently imploding vacuum bubbles. This process produces intense shear forces, mixing and disrupting droplets uniformly, resulting in nano-droplets with a consistent size distribution.
Hielscher Ultrasonics offers advanced devices for emulsion and nano-emulsion production, making it the preferred choice for enhancing product quality and performance.
Sonication for making an emulsion in a beaker
Hielscher Technical Center: Nanoflex DLS measurement for precise drople size measurement
Effects of Ultrasonic Intensity on Emulsion Quality
Emulsion quality is primarily determined by stability, influenced by droplet size distribution and emulsion formulation. Ultrasonic intensity, amplitude, and sonication duration are crucial factors affecting emulsion quality. High amplitudes and optimized sonication times lead to smaller, more stable droplets.
High-Performance Ultrasonic Emulsifiers
Ultrasonic emulsification is a reliable technology for producing high-quality emulsions with submicron and nano-sized droplets. Hielscher Ultrasonics offers a full range of devices from lab to industrial scale, ensuring the most suitable system for your emulsion process. Our team assists from feasibility tests to final production setup. The compact design and versatile installation options of our ultrasonic processors fit any processing facility.
Lab and Production, Batch and Inline Processing
Hielscher makes high-performance ultrasonic emulsifiers for small to large scale applications. Our benchtop systems are perfect for feasibility testing and process optimization. Scaling up is straightforward, either by upgrading to a more powerful unit or clustering multiple ultrasonicators. The UIP16000 is the world’s most powerful ultrasonic emulsifier. Customizable accessories enable the ideal configuration for your process, based on capacity, volume, raw materials, and production needs.
The table below indicates the processing capacity of our ultrasonicators for emulsification:
| Batch Volume | Flow Rate | Recommended Devices |
|---|---|---|
| 1 to 500mL | 10 to 200mL/min | UP100H |
| 10 to 2000mL | 20 to 400mL/min | UP200Ht, UP400St |
| 0.1 to 20L | 0.2 to 4L/min | UIP2000hdT |
| 10 to 100L | 2 to 10L/min | UIP4000hdT |
| n.a. | 10 to 100L/min | UIP16000 |
| n.a. | larger | cluster of UIP16000 |
Hielscher sonicators support both batch and continuous flow-through processing. Batch processing is ideal for testing and small to mid-size production, while inline processing is efficient for large volumes. Our systems are designed to meet your specific emulsion volume and process goals.
Ultrasonic Reactor for Production – UIP2000hdT
Precisely Controllable Amplitudes for Optimum Results
All Hielscher ultrasonicators are precisely controllable, ensuring efficient and effective emulsification. Amplitude is a key parameter that influences emulsion quality. Hielscher’s industrial processors can run continuously at high amplitudes, with settings that optimize sonication conditions for the best results. Our robust equipment is built for 24/7 operation in demanding environments.
Easy, Risk-free Testing
Ultrasonic processes are linearly scalable. Results achieved with lab or benchtop systems can be replicated on an industrial scale using the same parameters. This makes ultrasonication ideal for feasibility testing and process optimization. Contact us to learn how sonication can enhance your emulsion production.
Highest Quality – Designed and Manufactured in Germany
As a family-owned business, Hielscher prioritizes quality. Our ultrasonic processors are designed, manufactured, and tested in Germany, ensuring reliability and robustness for continuous operation under full load.
Frequently Asked Questions about Oil-in-Water Emulsions
What is an oil-in-water (O/W) emulsion?
An oil-in-water emulsion is a mixture where tiny droplets of oil are dispersed throughout a continuous water phase. Common examples include milk, mayonnaise, lotions, and salad dressings. The stability and quality of O/W emulsions depend on the emulsifying agents used and the mixing technique.
What is the best emulsifier for oil-in-water emulsions?
The best emulsifier depends on your application. Common choices include lecithin (food and cosmetics), polysorbates (pharmaceuticals), SDS (laboratory use), and natural proteins. Hielscher’s technical team can help you select the right emulsifier for your formulation.
What droplet size can ultrasonic emulsification achieve?
Hielscher ultrasonic processors can produce droplet sizes ranging from sub-micron down to 10 nanometers, creating stable nano-emulsions. Narrow droplet size distributions improve product clarity, stability, and bioavailability.
How does ultrasonic emulsification compare to high-pressure homogenization?
Ultrasonic emulsification offers several advantages:
- Smaller, more uniform droplet sizes
- Lower energy consumption
- Better control over processing parameters
- Easier scalability from lab to production
- Reduced heat generation with proper setup
Can ultrasonic emulsification be used for large-scale production?
Yes. Hielscher offers industrial processors up to 16,000W (sonicator model UIP16000hdT), capable of processing hundreds of liters per minute in continuous flow mode. Processes developed in the lab can be linearly scaled to production without re-optimization.
How do you stabilize an oil-in-water emulsion?
Stability is achieved through:
Emulsifiers/surfactants: Reduce interfacial tension between oil and water
Steric stabilizers: Polymers like PEG or PVA create physical barriers
Electrostatic stabilization: Ionic surfactants create repulsive charges
Small droplet size: Ultrasonic processing creates smaller, more stable droplets
Thickeners: Xanthan gum or carbomers increase viscosity
What is the difference between oil-in-water and water-in-oil emulsions?
In oil-in-water (O/W) emulsions, oil droplets are dispersed in water (e.g., milk, lotions). In water-in-oil (W/O)emulsions, water droplets are dispersed in oil (e.g., butter, margarine). The choice of emulsifier determines which type forms.
How long does ultrasonic emulsification take?
Sonication typically takes seconds to minutes, depending on volume, amplitude, and desired droplet size. This is significantly faster than traditional high-shear mixing, which can take 30+ minutes.
Is ultrasonic emulsification safe for food and pharmaceutical products?
Yes. Ultrasonic processing is a non-thermal, chemical-free method that does not introduce additives. It is widely accepted in food, cosmetic, and pharmaceutical applications.
What is a nano-emulsion?
A nano-emulsion is an emulsion with droplet sizes typically below 200 nanometers. These emulsions appear translucent, exhibit excellent stability, and offer enhanced bioavailability for active ingredients.
What is an example of an oil in water emulsion in pharmacy?
A common example is a lotion, where medicinal ingredients are dispersed in an oil-in-water emulsion for topical application.
Can you mix an oil-in-water emulsion with a water-in-oil emulsion?
Mixing these two types of emulsions is generally not recommended, as they have different continuous phases and can destabilize each other.
What is the best natural emulsifier for oil in water emulsion?
Natural emulsifiers like lecithin, beeswax, and certain proteins are effective for creating stable oil-in-water emulsions.
Can oil in water emulsions be diluted with water or oil?
Oil-in-water emulsions can be diluted with water, but adding oil may destabilize the emulsion and should be done cautiously.
What is the difference between Oil-in-Water and Water-in-Oil Emulsions?
The primary difference between these two emulsions is the composition of the suspension. In oil-in-water emulsions, oil is the dispersed phase distributed into the continuous phase, water. Conversely, in water-in-oil emulsions, water is the dispersed phase in oil. The choice of emulsifying agents significantly impacts the quality and stability of emulsions. While some nano-sized emulsions are naturally stable, most require carefully designed formulations for enhanced shelf life. Emulsifying agents must be compatible with the type of emulsion, as some are better suited for oil-in-water, while others work better for water-in-oil.
Literature / References
- O’Sullivan, Jonathan; Murray, Brian; Flynn, Cal; Norton, Ian (2015): Comparison of batch and continuous ultrasonic emulsification processes. Journal of Food Engineering, Volume 167, Part B, Dec. 2015, 114-121.
- Li, Yujie; Xiang, Dong (2019): Stability of oil-in-water emulsions performed by ultrasound power or high-pressure homogenization. PlosOne, March 8, 2019.
- Ramisetty, Kiran A.; Shyamsunder, R. (2011): Effect of Ultrasonication on Stability of Oil in Water Emulsions. International Journal of Drug Delivery, 3, 2011, 133-142.
Hielscher Ultrasonics manufactures high-performance ultrasonic homogenizers from lab to industrial size.