Characterized Ecoflex Polydimethylsiloxane (PDMS) Hybrids for Advanced Flexible Devices

ABSTRACT Silicone elastomers have garnered widespread attention for their flexibility, biocompatibility, and tunable mechanical properties. Among them, polydimethylsiloxane (PDMS) and Ecoflex, are widely used in soft electronics, microfluidics, and biomedical devices. However, the limited stretchability of PDMS (maximum strain < 165%) constrains its usage in flexible and stretchable devices, while Ecoflex though highly stretchable but lacks sufficient optical transparency and is incompatible with plasma bonding, restricting its integration into multilayer devices and high‐precision microfabrication. To overcome these challenges, we explored the Ecoflex–PDMS (EP) hybrids by blending the two materials in varying ratios. Systematic characterization of hybrids from pure PDMS (E0P10) to pure Ecoflex (E10P0) identified the 6:4 Ecoflex‐to‐PDMS ratio (E6P4) as optimal, balancing the stretchability, transparency, and plasma bonding strength. Specifically, E6P4 exhibits a Young's modulus of 0.314 MPa, Shore hardness of 70 (OO scale), maximum strain around 260%, and optical transmittance of 76% at 743.9 nm, and robust plasma bonding strength with a maximum peel force of 3.104 N. Leveraging these properties, we demonstrated its versatility in soft pneumatic gripper, flexible tactile sensors, and stretchable microfluidic devices for particle manipulation. This work establishes a versatile platform for multifunctional soft devices for robotics, wearable systems, and biomedical applications.