A polyimide-based thermal bridge

Thermal management across micro- to macro-scale critically depends on accurate characterization of intermediate-scale materials, such as individual fibers and thin films. Yet, measuring the thermal conductivity of a single fiber remains rather challenging. Here, we present a polyimide (PI)-based thermal bridge for accurate thermal transport measurement of single fibers and related microscale samples. By addressing key challenges in hybrid material integration and flexible substrate interconnection, our approach retains the mechanical flexibility of PI while achieving compatibility with conventional microfabrication processes. The PI suspension beams exhibit thermal conductance of ∼12 μW K-1, within one order of magnitude of similar devices made of SiNx, while their vertical stiffness is more than two orders of magnitude higher, providing exceptional stability for sample manipulation. Calibration using a standard 20 μm diameter platinum wire yields a measured thermal conductivity of 70.6 ± 3.6 W m-1 K-1, within 5% of the literature value (71.7 W m-1 K-1). With its robust mechanical design and reliable thermal performance, this PI-based thermal bridge offers a versatile platform for accurate characterization of individual fibers and films and holds great promise for advancing thermal management research.