Why Are Hydrogels Problematic for Electrodes?

Hydrogels are commonly used in electrode technology, but they come with several limitations. First, hydrogel-based materials can cause skin reactions in around 8% of users. Additionally, hydrogels are sensitive to environmental factors like temperature and humidity, which can affect their performance. 

These materials also tend to have a short shelf life once removed from their packaging, leading to potential waste. Lastly, hydrogel-based electrodes can be messy and difficult to handle, which is a common frustration for both users and healthcare professionals. 

From a very high level, think of a hydrogel as a wet sponge. The structural base of a hydrogel is a 3D, intertwined polymer network that is capable of absorbing and retaining water. To impart conductivity to most hydrogels, a salt that readily dissociates is added to the polymeric system, and it imparts electrical conductivity to these systems.  Conductivity increases as the salt/ion concentration increases, allowing one to tune the electrical performance of a hydrogel by concentration of salt in the system, but this can also lead to potential issues for patients. 

Skin irritation is one notable issue. Many patients experience discomfort with standard hydrogel compositions used for electrodes. However, research conducted by UMass Memorial Hospital and the UMass School of Medicine in a comparative 3-day clinical study demonstrated that Flexcon’s Omni-Wave™ technology caused significantly less skin irritation compared to traditional hydrogel-based electrodes. Omni-Wave™ technology does not leave red marks, is free from skin itchiness, leaves no residue around the edges, and can be removed without pain. 

In addition to skin irritation, hydrogels are dynamic materials that can be influenced by storage conditions. If not properly maintained, hydrogels may absorb or lose water, which can affect their performance. More concerning, however, is the loss of water, which can lead to inconsistent results, especially in patient monitoring. This water loss increases the complexity and cost of packaging, storing, and protecting hydrogel-based electrodes to ensure stable performance.

​In contrast to hydrogels, Flexcon’s Omni-Wave™ does not rely on water for its conductivity. Flexcon has developed a signal receptive material that utilizes the use of polar additives in pressure-sensitive adhesives. These polar additives are compatible with Flexcon's adhesive systems and allow the material to respond to and transmit bioelectrical signals effectively. Unlike hydrogel-based materials, the polar additive does not interfere with the adhesive's performance, maintaining strong adhesion for the required duration without causing skin irritation. 

Flexcon’s Omni-Wave™ technology, provides new possibilities in wearables, diagnostics, and wellness without the skin irritation, short shelf life, and expensive barrier packaging required for traditional hydrogel materials.

Request a sample of Flexcon’s Omni-Wave™.