The study addresses several persistent issues in capacitive sensor manufacturing: customization, reliability, and cost, each of which has limited their broader use in wearable and robotic systems.
Soft capacitive sensors play a central role in emerging technologies such as soft robotics, human-machine interfaces, and wearable health monitoring. These devices must be flexible, stretchable, and mechanically compliant while delivering stable and repeatable electrical signals.
However, many high-performance soft sensors rely on complex microstructuring or lithographic fabrication methods, which makes them difficult to scale or customize.
The new study addresses this gap by introducing a batch fabrication strategy that produces large-area, multilayer sensor sheets that can be rapidly customized into application-specific geometries.
Designing a Simple, Scalable Fabrication Strategy
Central to the new technique is a layer-by-layer casting process using film applicators, followed by laser cutting to define sensor shapes and electrode layouts.
Each sensor consists of five elastomeric layers: two protective layers, two conductive electrodes, and a central dielectric layer.
All layers are based on the same silicone elastomer (Ecoflex 00-30), a design choice that ensures strong interlayer adhesion and prevents delamination even in thin structures.
The study demonstrated experiments on sensors with individual layer thicknesses down to approximately 200 μm, with thinner layers theoretically achievable but limited by material viscosity during casting.
Carbon nanofiber (CNF)-based composite electrodes are produced by first dispersing the nanofibers in silicone oil, enabling higher filler loading and improved electrical conductivity.
The conductive composite is then shear blended into Ecoflex at a 15 wt% ratio, balancing conductivity with mechanical softness.
High-Dielectric Composites Improve Performance
To enhance sensitivity, the researchers incorporated high-dielectric fillers into the elastomeric dielectric layer, using barium titanate (BaTiO3) and titanium dioxide (TiO2).
Multiple filler concentrations were evaluated to understand both electrical and mechanical trade-offs.
Sensors using high-loading BaTiO3 composites showed the strongest performance gains, achieving a sensitivity of 0.55 kPa-1 and a gauge factor of 2.83 - substantially higher than many conventional capacitive sensors.
TiO2-based composites delivered more modest improvements, highlighting the importance of filler selection and loading.
The performance gains are driven by increased baseline capacitance, which improves signal-to-noise ratio and reduces susceptibility to parasitic capacitance, without requiring microstructured or porous dielectric architectures.
Stable Sensing Across Practical Pressure Ranges
The sensors exhibit a linear capacitive response up to approximately 200 kPa, covering pressure ranges relevant to human touch and object manipulation.
Across repeated loading cycles, hysteresis remains below 10 %, and performance is stable over thousands of compressive cycles.
Dynamic testing shows response and recovery times on the order of 120-170 milliseconds, supporting the use of these sensors in real-time tactile and pressure-sensing applications.
Individual Sensors to Wearable Tech
Beyond single devices, the fabrication method supports the rapid production of sensor arrays. By using a masking technique during deposition of the second electrode layer, the researchers created patterned arrays without additional processing steps.
As a demonstration, a four-sensor array was integrated into a glove and used to measure distributed pressure while a user held a beaker as water was poured in.
The array successfully distinguished contact and load variations across individual sensors, illustrating its potential for wearable tactile sensing in robotics and health monitoring.
Practical Soft Sensing
Rather than focusing solely on record-breaking sensitivity, the study emphasizes manufacturability, customization, and reliability.
By combining straightforward casting, uniform material chemistry, and laser-based patterning, the approach offers a practical route to producing soft capacitive sensors at scale.
The work positions batch-fabricated, high-dielectric composite sensors as a viable platform for next-generation soft sensing technologies, particularly in applications where conformability, durability, and tailored geometry are as important as raw sensitivity.
Journal Reference
Ali G., et al. (2026). Customized batch fabrication of highly sensitive thin capacitive soft sensors based on high dielectric constant composite polymers. Scientific Reports 16, 1543. DOI: 10.1038/s41598-025-27387-x