TY - JOUR
T1 - Strategies to control humidity sensitivity of azobenzene isomerisation kinetics in polymer thin films
AU - Vesamäki, Sami
AU - Meteling, Henning
AU - Nasare, Roshan
AU - Siiskonen, Antti
AU - Patrakka, Jani
AU - Roas-Escalona, Nelmary
AU - Linder, Markus
AU - Virkki, Matti
AU - Priimagi, Arri
PY - 2024/12
Y1 - 2024/12
N2 - Azobenzenes are versatile photoswitches that garner interest in applications ranging from photobiology to energy storage. Despite their great potential, transforming azobenzene-based discoveries and proof-of-concept demonstrations from the lab to the market is highly challenging. Herein we give an overview of a journey that started from a discovery of hydroxyazobenzene’s humidity sensitive isomerisation kinetics, developed into commercialization efforts of azobenzene-containing thin film sensors for optical monitoring of the relative humidity of air, and arrives to the present work aiming for better design of such sensors by understanding the different factors affecting the humidity sensitivity. Our concept is based on thermal isomerisation kinetics of tautomerizable azobenzenes in polymer matrices which, using pre-defined calibration curves, can be converted to relative humidity at known temperature. We present a small library of tautomerizable azobenzenes exhibiting humidity sensitive isomerisation kinetics in hygroscopic polymer films. We also investigate how water absorption properties of the polymer used, and the isomerisation kinetics are linked and how the azobenzene content in the thin film affects both properties. Based on our findings we propose simple strategies for further development of azobenzene-based optical humidity sensors.
AB - Azobenzenes are versatile photoswitches that garner interest in applications ranging from photobiology to energy storage. Despite their great potential, transforming azobenzene-based discoveries and proof-of-concept demonstrations from the lab to the market is highly challenging. Herein we give an overview of a journey that started from a discovery of hydroxyazobenzene’s humidity sensitive isomerisation kinetics, developed into commercialization efforts of azobenzene-containing thin film sensors for optical monitoring of the relative humidity of air, and arrives to the present work aiming for better design of such sensors by understanding the different factors affecting the humidity sensitivity. Our concept is based on thermal isomerisation kinetics of tautomerizable azobenzenes in polymer matrices which, using pre-defined calibration curves, can be converted to relative humidity at known temperature. We present a small library of tautomerizable azobenzenes exhibiting humidity sensitive isomerisation kinetics in hygroscopic polymer films. We also investigate how water absorption properties of the polymer used, and the isomerisation kinetics are linked and how the azobenzene content in the thin film affects both properties. Based on our findings we propose simple strategies for further development of azobenzene-based optical humidity sensors.
UR - http://www.scopus.com/inward/record.url?scp=85205834990&partnerID=8YFLogxK
U2 - 10.1038/s43246-024-00642-w
DO - 10.1038/s43246-024-00642-w
M3 - Article
AN - SCOPUS:85205834990
SN - 2662-4443
VL - 5
JO - Communications Materials
JF - Communications Materials
IS - 1
M1 - 209
ER -