This study uses rapid 35-75-35-75-35°C cycling and impedance spectroscopy to generate water-rich and water-poor states in one bacterial-cellulose composite containing about 10 wt% titanate nanotubes. Conductivity was nearly additive when hydrated but fell toward cellulose values upon dehydration.
Key findings
- Hydrated composite conductivity was approximately additive; dehydration lowered it and raised grain resistance above water-poor BC. Relaxation time increased from about 5.2 to 31.8 μs. AFM showed heterogeneous conduction, XRD retained cellulose structure, and TGA shifted the water-loss peak upward.
Why this matters globally
Rapid cycling may screen hydrated materials for sensors, electrolytes, or bioelectronics faster than conventional humidity chambers, but devices require precise hydration and hysteresis control.
Thai researcher contribution
KMITL, Mahidol, and KMUTNB researchers combined composite fabrication with electrical, AFM, X-ray, and thermal evidence across multiple scales.
Limitations to consider
One composition and short cycling were tested. Temperature changes hydration and carrier mobility together, limiting separation. Replication, long-term cycling, ambient-humidity response, and aging are not reported; PTCR is apparent rather than an intrinsic fixed coefficient.