Synthesis and characterization of polyaniline doped with organic acids

Spectroscopic [UV–visible and Fourier transform IR (FTIR)] and thermal properties of chemically synthesized polyanilines are found to be affected by varying the protonation media (acetic, citric, oxalic, and tartaric acid). The optical spectra show the presence of a greater fraction of fully oxidized insulating pernigraniline phase in polyaniline doped with acetic acid. In contrast, the selectivity in the formation of the conducting phase is higher in oxalic acid as a protonic acid media. The FTIR spectra of these polymers reveal a higher ratio of the relative intensities of the quinoid to benzenoid ring modes in acetic acid doped polyaniline. Scanning electron micrographs revealed a sponge‐like structure derived from the aggregation of the small granules in acetic acid and oxalic acid doped polyaniline. A three‐step decomposition pattern is observed in all the polymers, regardless of the protonic acid used for the doping. The second step loss related to the loss of dopant is found to be higher in the oxalic acid doped polymer. In accordance with these results the conductivity is also found to be higher in oxalic acid doped material. The temperature dependent conductivity measurements show the thermal activated behavior in all the polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2043–2049, 2004     

Strategic commitment to price to stimulate downstream innovation in a supply chain

It is generally in a firm’s interest for its supply chain partners to invest in innovations. To the extent that these innovations either reduce the partners’ variable costs or stimulate demand for the end product, they will tend to lead to higher levels of output for all of the firms in the chain. However, in response to the innovations of its partners, a firm may have an incentive to opportunistically increase its own prices. The possibility of such opportunistic behavior creates a hold-up problem that leads supply chain partners to underinvest in innovation. Clearly, this hold-up problem could be eliminated by a pre-commitment to price. However, by making an advance commitment to price, a firm sacrifices an important means of responding to demand uncertainty. In this paper we examine the trade-off that is faced when a firm’s channel partner has opportunities to invest in either cost reduction or quality improvement, i.e. demand enhancement. Should it commit to a price in order to encourage innovation, or should it remain flexible in order to respond to demand uncertainty. We discuss several simple wholesale pricing mechanisms with respect to this trade-off.     

EPR studies of a molybdenyl complex in single crystals of NH4Cl

Electron paramagnetic resonance of [MoOCl₅]^2? has been studied in single crystals of NH₄Cl. At room temperature the interaction of the unpaired electron with both the even and odd isotopes of molybdenum has been observed. The existence of metal-halogen π bonding is established by the observation of the ligand superhyperfine interaction at liquid nitrogen temperatures. Various possible models corresponding to the different spatial configurations of the molybdenyl complex in the lattice are considered to explain the experimentally observed features. The spectra are analysed using the usual spin-hamiltonian corresponding to tetragonal symmetry. The spin-hamiltonian parameters obtained are: g_∥ = 1.964, g_? = 1.945, A_∥ = 75.53 × 10^?4 cm^?1, A_⊥ = 38.42 × 10^?4 cm^?1.     

Adoption and use of AI tools: a research agenda grounded in UTAUT

This paper is motivated by the widespread availability of AI tools, whose adoption and consequent benefits are still not well understood. As a first step, some critical issues that relate to AI tools in general, humans in the context of AI tools, and AI tools in the context of operations management are identified. A discussion of how these issues could hinder employee adoption and use of AI tools is presented. Building on this discussion, the unified theory of acceptance and use of technology is used as a theoretical basis to propose individual characteristics, technology characteristics, environmental characteristics and interventions as viable research directions that could not only contribute to the adoption literature, particularly as it relates to AI tools, but also, if pursued, such research could help organizations positively influence the adoption of AI tools.

     

Spreading and retraction dynamics of smectic liquid crystal domains at interfaces

The spreading of a liquid drop over liquid subphase can be driven by change in interfacial tension mediated through a surfactant, volatile solvent or photoinduced reaction. In contrast to the spreading dynamics of a liquid drop, a liquid crystal drop with anisotropic structure can lead to interesting behaviour due to its viscoelasticity and anchoring at the interfaces. Recently, we have reported studies on unusual spreading and retraction dynamics of a smectic domain doped with a fluorescent dye in the collapsed state of a Langmuir monolayer. Under epifluorescence microscope, during excitation, a stack of layers of the dye-doped smectic domain gets sheared causing the domain to spread asymmetrically. Further, due to line tension, the domain transforms into a circular shape. We also find the domain size to be about twice that of the initial size. Interestingly, in the absence of excitation, the domain retracts to a smaller area. During retraction of the domain, successive generation of edge dislocation loops arising from a nucleus results in an increase in the domain thickness. The dynamics of spreading and retraction of the domain can be understood by invoking changes in the spreading coefficient due to photoinduced modification of the interfacial tension.     

Studies on the cure parameters of cyanate ester–epoxy blend system through rheological property measurements

Thermosetting blend system of co-cured cyanate ester with epoxy resin is receiving importance for high technological applications because of its wide range of thermo-mechanical, rheological, and electrical properties. However, processing of these system warrant proper knowledge of the rheological behavior of the blend during the curing process. This article discusses the rheological behavior of the blend systems with respect to the pot life, gel time, gelation temperature and also evaluated fitting parameters for the prediction of gelation time and viscosity during the entire curing process from the isothermal rheological measurements.