ITO Coating for Electro-Wetting Applications

Precision Surface Engineering for Electro-wetting and Microfluidic Innovation

The development of microfluidics has created an increasing need for material that can deliver precise electrical performance at extremely small scales. One material particularly suited to these applications is Indium Tin Oxide (ITO)

Diamond Coatings provides advanced Indium Tin Oxide (ITO) coating solutions engineered specifically for electro-wetting systems and microfluidic device applications. Our coatings combine exceptional optical transparency with high electrical conductivity—enabling precise control of fluid behaviour at the microscale.

From research and prototype development to larger-scale manufacturing, carefully controlled ITO coatings can provide the functional surface required for next-generation microfluidic technologies.

What is ITO Coating?

Indium Tin Oxide (ITO) is a transparent conductive oxide, that combines electrical conductivity with optical transparency. This combination has made ITO an important material across numerous technologies, including displays, optical systems, sensors and specialist electronic devices.

ITO can be deposited as a thin film onto a suitable substrate, creating an electrically conductive surface while allowing light to pass through. The coating can be engineered around requirements including film thickness, sheet resistance, optical transmission and surface characteristics.

These properties are particularly valuable in electro-wetting and microfluidic systems.

What is Electro-Wetting?

Electro-wetting is a technique that uses applied electrical potential to modify how liquid reacts with a surface.

At a microscale, this principle can be used to provide highly controlled manipulation of individual drops. Droplets can potentially be moved and positioned across a surface using electrical signals.

The ability to manipulate extremely small liquid volumes makes electro-wetting particularly attractive for digital microfluidics and lab-on-a-chip technologies, where compact devices can be designed to perform complex fluid-handling operations. 

What is ITO Coating for Electro-Wetting?

A key component within many electro-wetting systems is the electrode used to apply an electrical potential.

While conventional conductive materials can perform this function, many microfluidic devices also require optical access. Researchers may need to observe droplets through a microscope, capture images or integrate optical sensing technologies into the device.

At the core of the electro-wetting process is the conductive, transparent surface- this is where ITO coating plays a critical role as it can act as a transparent conductive electrode. ITO coating provides the electrical functionality needed by the device while allowing light to pass through the substance. This can be particularly useful in systems combining electrical droplet manipulation with imaging, sensing or optical measurement.

Diamond Coatings ITO thin films provide:

• Uniform conductivity across complex substrates
• High optical transparency for imaging and sensing
• Strong adhesion and durability under repeated actuation cycles

These properties make ITO an ideal material for lab-on-chip devices, digital microfluidics, and advanced biomedical systems.

ITO within an Electro-Wetting Device

The ITO coating usually forms one part of a more complex, multi-layer structure. The performance of the underlying ITO layer can therefore affect subsequent manufacturing stages as well as the finished device.

Surface characteristics, coating uniformity, electrical properties and compatibility with additional materials should ideally be considered during the early stages of device development.

Rather than treating the ITO coating simply as a conductive coating, it is important to consider how it integrates into the complete microfluidic system.

Why Choose Diamond Coatings?

At Diamond Coatings we understand that electro-wetting and microfluidic systems require precision at every stage of their construction. Our ITO coatings are developed with tight process control to ensure consistency, repeatability, and reliability.

Key advantages:

• High Uniformity: Consistent sheet resistance across the substrate
• Custom Thickness Control: Tailored to your electrical and optical requirements
• Low Surface Roughness: Optimised for droplet mobility and stability
• Scalable Production: From R&D prototypes to full-scale manufacturing
• Substrate Flexibility: Glass, silicon, polymers, and specialty materials

Applications

Our ITO coatings have a combination of electrical conductivity, transparency and thin-film construction that can support a variety of advanced applications:

• Digital microfluidic platforms- ITO coatings can support precise manipulation of individual liquid droplets.
• Lab-on-a-chip diagnostic systems- can integrate multiple laboratory processes into compact devices
• Biomedical research devices- can benefit from precise handling of small liquid volumes combined with optical observation or detection.
• Optical sensing and imaging systems- may require an electronically functional surface without obstructing the optical path through the device.
• Adaptive lenses and display technologies- electrical signals are used to control the behaviour of liquids within an optical system.

Whether you’re developing next-generation diagnostics or fluid control systems, our coatings provide the functional foundation your technology depends on.

Engineered for Performance

Electro-wetting systems demand coatings that perform under electrical stress while maintaining optical clarity and chemical stability. Our ITO layers are engineered to:

• Maintain conductivity under repeated voltage cycling
• Resist degradation in fluidic environments
• Enable precise droplet actuation and positioning
• Integrate seamlessly with dielectric and hydrophobic layers

Collaborative Development

We work closely with clients to optimise coating specifications for their specific application. From early-stage feasibility to production scaling, our technical team provides hands-on support so that an appropriate coating solution can be developed.

This collaborative approach helps ensure that the coating is developed as part of the overall device rather than considered as an isolated component.

Diamond Coatings operates multiple custom state of the art vacuum coating plants across our manufacturing locations in the UK and USA. The unique vacuum coatings system and technology we have developed enables Diamond Coatings to offer our high quality ITO and optical coatings vacuum deposited on many substrate types. As well as all glass types, Diamond Coatings ITO can be vacuum deposited onto many other substrates such as Optical PMMA and Polycarbonates and also COP substrates such as Zenor and Zeonex.

Diamond Coatings support our customers across the full range of vacuum coating production requirements, from prototypes to low & medium production runs, all the way up to high volume production requirements reaching millions of parts per year.

Diamond Coatings can provide a vacuum coating-only service, as well as a complete supply service where we manage both our vacuum coatings and the substrates.

Get in Touch

Ready to enhance your electro-wetting system with high-performance ITO coatings?

Contact Diamond Coatings today to discuss your project requirements or request a consultation with our technical team.

Diamond Coatings – Enabling Precision at the Microscale