Multi-mode humidity sensing with water-soluble copper phthalocyanine for increased sensitivity and dynamic range.

Aqueous solubility of copper phthalocyanine-3,4',4″,4″'-tetrasulfonic acid tetrasodium salt (CuPcTs) enables fabrication of flexible electronic devices by low cost inkjet printing. We (1) investigate water adsorption kinetics on CuPcTs for better understanding the effects of relative humidity (RH) on hydrophilic phthalocyanines, and (2) assess CuPcTs as a humidity-sensing material. Reaction models show that HO undergoes 2-site adsorption which can be represented by a pair of sequentially-occurring pseudo-first order reactions.

New Insights on Electro-Optical Response of Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Film to Humidity.

Understanding the relative humidity (RH) response of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is critical for improving the stability of organic electronic devices and developing selective sensors. In this work, combined gravimetric sensing, nanoscale surface probing, and mesoscale optoelectronic characterization are used to directly compare the RH dependence of electrical and optical conductivities and unfold connections between the rate of water adsorption and changes in functional properties of PEDOT:PSS film. We report three distinct regimes where changes in electrical conductivity, optical conductivity, and optical bandgap are correlated with the mass of adsorbed water.

The science behind codes and standards for safe walkways: changes in level, stairways, stair handrails and slip resistance.

Walkway codes and standards are often created through consensus by committees based on a number of factors, including historical precedence, common practice, cost, and empirical data. The authors maintain that in the formulation of codes and standards that impact pedestrian safety, the results of pertinent scientific research should be given significant weight. This article examines many elements of common walkway codes and standards related to changes in level, stairways, stair handrails, and slip resistance.

The development of a universal approach to testing of walkway slip resistance in the U.S.

The measurement of walkway slip resistance is required to assess the risk of slipping. Unlike other countries, the U.S.