Valved microfluidics with Ostemers

Poly(dimethylsiloxane) (PDMS) is the material of choice for fabricating high-performance microfluidic devices, yet its intrinsic limitations, such as poor surface wettability, chemical instability, and porosity, continue to constrain device functionality and material integration. Ostemer polymers, a versatile family of hybrid thermoset-elastomers, present an attractive alternative owing to their excellent chemical resistance, compatibility with surface modification, tunable mechanical properties and ease of scalable fabrication. Here, for the first time, we introduce a process employing Ostemers for the realization of valved microfluidic architectures. The device features a three-layer stack design that decouples the roles of the flow, membrane, and control layers, enabling optimized performance and flexible material combinations. The valve membrane, composed of the optical adhesive NOA-84, exhibits predictable deflection behavior in agreement with theoretical models under pneumatic actuation. The fabricated valves (75 × 75 μm² chip1 and 100 × 145 μm² chip4 membrane area) achieve switching transition times of approximately 200 ms, comparable to PDMS-based systems. Furthermore, we demonstrate long-term operational stability in ultrathin, flexible devices, as well as sustained performance under exposure to chemically aggressive environments. This Ostemer-based platform effectively addresses the chronic shortcomings of PDMS microfluidics, paving the way toward next-generation microfluidic systems with enhanced integration, durability, and functional diversity.