Title
Cobalt chloride-based humidity sensor attached to sol-gel modified cellulosic material
Authors
CHRISTIAN SCHRAMM ANGELIKA KITZKE and RICHARD TESSADRI

Received February 12, 2016
Published Volume 51 Issue 3-4 March-April
Keywords cotton, sol-gel, humidity sensor, organic-inorganic hybrid, cobalt chloride hexahydrate

Abstract
Humidity sensors are important for assessment of environmental monitoring and industrial applications. Various kinds of humidity sensors, based on different materials and sensing principles, have been developed. In the present paper, cotton fabrics were impregnated using finishing baths containing different alkoxysilanes: tetraethoxysilane (T+EOS), (3-aminopropyl)triethoxysilane (APTES) and (3-triethoxysilylpropyl)succinic acid anhydride (TESP-SA) in combination with cobalt chloride hexahydrate as humidity indicating substance. The rates of color change of the cobalt chloride-doped fabrics were evaluated by measuring the change of the K/S values at three relative humidity (r.H.) levels (12%, 55% and 86%). The modified specimens were characterized by means of SEM, FT-IR and TGA. The physical-technical properties were assessed (air permeability, flexural rigidity, tensile strength, abrasion resistance). The findings make evident that the sol-gel modification results in a decrease in the rates of color change. The APTES treated specimen showed no change of color.