Development of a Graphene Oxide/Styrene‐Butadiene Latex Composite Thin‐Film for Resistive Humidity Sensing

ABSTRACT In this study, a graphene oxide (GO)–styrene‐butadiene latex (SBL) composite thin film was developed and evaluated as a resistive‐type humidity sensor. The sensor was fabricated by drop‐coating a GO/SBL suspension onto a flexible interdigitated substrate with gold microelectrodes. The primary aim was to enhance film adhesion and sensing stability by blending GO with SBL, overcoming delamination issues seen with pure GO films. The optimal GO:SBL weight ratio was determined to be 2:1, providing the highest sensitivity and linearity across a wide relative humidity (RH) range of 11%–97% at 25°C. The sensor demonstrated a sensitivity of 1.01 ΔR/R/%RH, with response and recovery times of 31 and 36 s, respectively. Repeatability tests over five RH cycles showed less than 2% variation, and stability was confirmed for 60 days under ambient conditions. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses confirmed uniform film morphology and dispersion. Compared with pure GO films, the GO/SBL sensor showed significantly improved adhesion, linear response behavior, and environmental robustness. These findings suggest that the GO/SBL composite film is a strong candidate for long‐term, flexible MEMS‐based humidity sensing applications.