Poly(acrylic acid) (PAA) was decarboxylated in aqueous solution as a function of pH and ionic strength in the temperature range 100–350°C. Degradation kinetics were first order with respect to acid functionality. The rate of decarboxylation at high pH (Eα = 51.1 kcal/mol) was much slower than that at low pH (Eα = 20.3 kcal/mol). At intermediate pH, the reactivity was found to depend on the degree of dissociation of PAA as a functions of ionic strength, pH, and temperature. No monomer was observed in the reaction product. © 1996 John Wiley & Sons, Inc.

Flexible and stretchable polyurethane/carbon nanotube composite with strain detection ability was used for human breath monitoring. The composite material consisted of a network of multiwalled carbon nanotubes and thermoplastic high elastic polyurethane. It was found that elongation of the composite led to a macroscopic increase in electrical resistance, which can be used as a principle for applied strain detection. This detection was reversible, durable, and sensitive with gauge factor reaching very promising value, as, for example, ~46 at applied deformation of 8.7%. Further, the composite could be elongated to very large extend of deformation without discontinuity in measured resistance change reaching gauge factor ~ 450 at composite mechanical break at ~300% of strain. Sensor durability was also confirmed by sine wave deformation cycling when any decrease in the sensor properties for more than 103 cycles was observed. Simultaneously, the prepared composite possessed other utility properties also and was considered as multifunctional when it was tested as an organic solvent vapor sensor, an element for Joule heating and finally as a microstrip antenna.

The high sensitivity in response, selectivity and reversibility was achieved on a carbon nanowall-based sensor for the vapor detection of volatile organic compounds, which were tested by an electrical resistance method during adsorption and desorption cycles.

No abstract

This article describes the construction of an antenna that operates at frequencies of 1.07, 1.5, and 2.49 GHz and that is fabricated on a flexible polymer substrate using inkjet printing technology. In particular, this article is focused on the preparation and characterization of an antenna starting from the ink formulation for printing a homogeneous, electrically conductive layer using silver nanoparticles. The diameter of the prepared silver nanoparticles ranges from 50 to 200 nm. The inkjet printing technology on flexible polymer substrates offers a wide range of applications where there are high demands for flexibility. In combination with the polymer substrate, inkjet printing enables the production of more complex shapes and curves for antennas that are widely applicable not only in wearable electronic devices but also in plastic cases for portable communication devices.