Can water-based ink conduct electricity?
Date: Jun 04 2025 From: Star Color Views:
With the rapid development of printing inks today, conductive inks have become core materials in modern electronic printing, flexible circuits, smart packaging, and other fields. From the precision flexible circuits of smart devices to the intelligent labels of commercial packaging, conductive inks inject vitality into various electronic products and smart applications with their unique conductive properties.
However, traditional solvent-based conductive inks release volatile organic compounds (VOCs) during use, threatening the environment and human health. With the popularization of environmental protection concepts, water-based inks have come into the spotlight. So, do water-based inks have conductive capabilities?
I. Basic Composition and Conductivity Principles of Water-based Inks
1.1 Composition of Ordinary Water-based Inks
Ordinary water-based inks are mainly composed of water-based resins, pigments, additives, and water. Among them:
- Water-based resins serve as film-forming substances, endowing the ink with adhesion properties.
- Pigments determine the color of the ink.
- Additives are used to adjust ink performance.
- Water acts as a solvent to ensure good fluidity and coating properties of the ink.
1.2 Reasons for Lack of Conductivity
In general, water-based inks do not have conductivity. This is because their pigments are mostly non-metallic materials that cannot conduct electric current, and polymer resins are insulators, making it difficult to form electron transmission channels.
1.3 Key Materials for Achieving Conductivity
To make water-based inks conductive, conductive fillers must be added. Common ones include:
- Conductive carbon materials: Such as carbon black, carbon nanotubes, and graphene. For example, carbon nanotubes can build a good conductive network in inks due to their high aspect ratio and excellent conductivity.
- Metal powders: Silver powder, copper powder, silver nanowires, etc. Silver powder has strong conductivity and good chemical stability but is costly; copper powder is low-cost but prone to oxidation and requires special treatment.
- Conductive polymers: Such as PEDOT:PSS, which is not only conductive but also has excellent film-forming and flexible properties, showing broad application prospects in the field of flexible electronics.
The conductivity of water-based inks depends on the formation of continuous conductive paths between conductive particles, which poses great challenges in ink formulation, appropriate solid content, raw material selection, and production processes. Uniform dispersion, good film-forming properties, and adhesion will all affect conductivity.
The biggest challenge in water-based systems is
how to stably disperse hydrophobic conductive particles and prevent agglomeration and precipitation. Huizhou Starcolor is also continuously researching and improving in this regard.
II. Realization Methods of Water-based Conductive Inks
2.1 Construction of Dispersion Systems
Water-based conductive inks typically consist of a water-based carrier and conductive fillers to form a dispersion system. However, conductive fillers have high surface energy and are prone to agglomeration in water, leading to uneven dispersion and affecting the ink’s conductive properties and printing suitability.
2.2 Solutions to Dispersion Challenges
To solve dispersion problems, researchers have adopted various technologies:
- Surface modification: Chemically modifying the surface of conductive fillers to enhance hydrophilicity and improve dispersion stability in water.
- Use of dispersants: Dispersants adsorb on the surface of fillers to form a protective film, preventing agglomeration, reducing the surface tension of the system, and promoting dispersion.
- pH control: Adjusting the pH of the system to change the charge properties of the filler surface and achieve stable dispersion through electrostatic repulsion.
2.3 Common Types and Performance Indicators
Based on different conductive materials, water-based conductive inks are divided into water-based carbon-based conductive inks, water-based silver paste conductive inks, water-based conductive polymer inks, etc. Key indicators for measuring their performance include:
- Electrical properties: Surface resistance and volume resistance, which directly reflect conductive capabilities.
- Application properties: Film-forming ability, adhesion, flexibility, and water resistance, which determine the applicability and reliability of practical applications.
III. Application Fields of Water-based Conductive Inks
3.1 Smart Packaging Labels
Water-based conductive inks play a significant role in the smart packaging field. NFC and RFID antennas are the core of smart packaging labels. Printing with water-based conductive inks enables low-cost, large-area preparation of antennas. In addition, printed resistive circuits can endow labels with functions such as temperature monitoring and humidity sensing, promoting the intelligence of packaging.
3.2 Flexible Electronic Products
Flexible electronic products are an important application direction for water-based conductive inks. Wearable devices such as smart bracelets and smart clothing require flexible and comfortable electronic components. Electric heating films, sensors, etc., printed with water-based conductive inks, have good electrical conductivity and can closely bond with flexible substrates. They also have broad prospects in flexible displays and flexible batteries.
3.3 Touch and Display Fields
In the touch display field, capacitive touchscreens are widely used. Transparent conductive electrodes printed with water-based conductive inks have both good electrical conductivity and optical transparency, meeting the performance requirements of touchscreens. In electrochromic devices, water-based conductive inks used as electrode materials can change colors through voltage changes, showing great potential in smart windows, electronic billboards, and other fields.
3.4 Paper Circuits and Educational Electronic Paper
With the enhancement of environmental awareness, paper circuits and educational electronic paper have developed rapidly. Water-based conductive inks, using water as a solvent, are environmentally friendly and non-toxic, suitable for printing paper-based circuits. Printing conductive lines on paper can produce eco-friendly low-voltage circuit boards for electronic education and children’s toys, bringing new educational and entertainment experiences.
3.5 Medical Printable Devices
In the medical field, water-based conductive inks have unlimited potential. Disposable biological sensors, microelectrodes, and other medical printable devices require materials with good biocompatibility and safety. Water-based conductive inks can meet these requirements, and high-precision, low-cost medical devices can be prepared through printing technology for disease diagnosis and health monitoring.
Conclusion
Water-based inks themselves do not have conductivity, but through the rational addition of conductive materials and modified dispersion technologies, water-based conductive inks with both environmental protection and conductive properties can be prepared.
Such materials are important supports for realizing green electronic printing, smart packaging, and wearable devices. Starcolor will continue to deepen its research in this field and promote the large-scale application of green functional materials in industries.
RU
EN
CN
