Tu-POS-08 - Irreversible Microstructured Optical RH Threshold Indicator with a Binary Visual Readout

Event

EUROSENSORS 2026
2026-09-06 - 2026-09-09
Zurich

Band

Poster

Chapter

Photonics And Optical Sensors

Author(s)

J. Orlikowski, J. Cybińska - Łukasiewicz Research Network – PORT Polish Center for Technology Development,Wrocław (Poland)

Pages

537 - 538

DOI

10.5162/eurosensors2026/Tu-POS-08

ISBN

978-3-910600-12-6

Price

free

Abstract

A passive optical relative humidity threshold indicator is presented for irreversible recording of selected humidity exceedance events. The system is based on a low-cost, humidity-responsive biopolymer film with functional additives selected with future application and biocompatibility requirements in mind. Exposure to the assigned humidity threshold triggers disappearance of a visible structural-optical response, which remains absent after return to the reference humidity. Representative threshold variants showed complete visual loss of diffraction after exposure to RH values of 60, 70 and 80 percent, while the diffractive response remained visible after exposure to the highest sub-threshold RH level tested under the applied exposure protocol. The transition was confirmed by reflected optical intensity measurements. The concept offers a simple, battery-free route toward passive humidity threshold labels.