Chemical bonding boosts durability of flexible strain sensors

Researchers developed a carbon nanotube-based strain sensor that stays stable through 15,000 stretch cycles and harsh acidic, alkaline and saline conditions. The design could strengthen wearable health monitoring and industrial sensing where long-term durability has been a bottleneck.

Why it matters: - Wearable strain sensors can track subtle signals like heartbeats and pulses, as well as larger motions such as elbow bending. - Long-term drift and environmental instability have limited real-world use in health monitoring and industrial settings. - The new design aims to keep sensing performance stable under repeated stretching and harsh chemical exposure.

What happened: - Researchers developed an ultra-durable carbon nanotube strain sensor using a dual-modification strategy. - The sensor combines in-situ silica growth, mercaptosilane surface grafting and a covalent co-vulcanization network in styrene-butadiene rubber and carbon nanotube composites. - The work was published Aug. 12, 2026, with DOI 10.1016/j.wees.2026.04.001.

The details: - The in-situ silica and mercaptosilane treatment suppresses secondary agglomeration of conductive fillers. - The covalent network anchors conductive pathways in the rubber matrix. - The sensor maintained stable signal output without significant drift after 15,000 stretch cycles. - The device operated reliably in strong acid, strong base and highly saline environments. - The method uses a two-step functionalization process with TEOS and KH590. - The process improved filler dispersion and lowered the Payne effect.

Between the lines: - The technical shift is away from weak van der Waals-based filler interactions and toward direct chemical bonding. - That matters because re-aggregation of conductive fillers is a common reason flexible sensors lose performance over time. - The study suggests multi-scale hybridization can help close the gap between high sensitivity and long service life.

What's next: - The researchers say the approach could support reliable health monitoring devices. - The same durability profile could also fit high-risk industrial scenarios where sensors face repeated strain and chemical exposure. - The study was funded by the National Natural Science Foundation of China, the Shandong Provincial Higher Education Institutions Youth Innovation Technology Support Program, the Natural Science Foundation of Shandong Province and the Taishan Scholars Young Experts Program of Shandong Province.