23 research outputs found
Microwave assisted electrolysis of alkaline water solution
The effect of microwaves (MW) on the electrolytic process of 6M KOH water solution is investigated in the temperature range from 291 K to 337 K. At lower temperatures, microwaves facilitate electrolytic process, whereas the effect is reversed at higher temperatures.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200
Enhanced microwave synthesis of polyaniline nanomaterials
Energy- and time-efficient enhanced microwave syntheses (EMS) of polyaniline (PANI) have been carried out. The GPC results showed that the molecular weight of the microwave-generated materials depends on the applied microwave power. FTIR spectroscopies confirmed the formation of PANI. The presence of a mixed morphology with the prevalence of nanofibers with different aspect ratios is confirmed through SEM. The conductivity of the samples (ca. 3-3.5 S cm-1) is found to be relatively independent on the microwave power levels. The fact that the molecular weight depends on the power means that this approach can be fine-tuned to optimize conditions for a specific material using different power levels
Enhanced Microwave Synthesis: Fine-Tuning of Polyaniline Polymerization
A series of energy- and time-efficient enhanced microwave
syntheses
(EMS) of polyaniline (PANI) have been performed and are discussed
herein. The syntheses were performed at different microwave power
levels while keeping the reaction system at a constant temperature
of 24 ± 1 °C, with the samples extracted after 10 min of
reaction. Molecular weights were determined with GPC (gel permeation
chromatography) and showed that the molecular weight of the microwave-generated
materials depends on applied power: the higher the power level, the
greater the molecular weight. The chemical structure was investigated
by FTIR and UV–vis spectroscopy, while the morphology was imaged
using scanning electron microscopy (SEM). FTIR and UV–vis spectroscopy
confirmed the formation of PANI, and SEM indicated the presence of
a mixed morphology, with a prevalence of nanofibers with different
aspect ratios. The conductivity of the samples (ca. 3–3.5 S
cm<sup>–1</sup>) was found to be relatively independent of
microwave power levels. Surface area measurements were carried out
using Brunauer–Emmett–Teller (BET) method, with samples
synthesized using EMS showing higher surface areas when compared with
conventionally synthesized PANI. The fact that molecular weight depends
on applied power implies that microwave-enhanced synthesis can be
used to fine-tune PANI reaction conditions, directing it toward specific
properties
Antimicrobial activity of polyaniline and pullulan composites synthetized using microwave radiation
The aim of this study is to synthesize PANI/pullulan composites using microwave radiation and investigate their microbial activity
Determination of critical micelle concentration of cetyltrimethylammonium bromide: Different procedures for analysis of experimental data
Conductivity of two micellar systems was measured in order to determine
critical micelle concentration (CMC) of cetyltrimethylammonium bromide
(CTAB). Those systems were: CTin water and CTin binary mixture
acetonitrile (ACN)-water. Conductivity (κ)-concentration (c) data were
treated by four different methods: conventional method, differential methods
(first and second derivative) and method of integration (methods A-D,
respectively). As CTin water micellar system shows a sharp transition
between premicellar and postmicellar part of the κ/c curve, any of the
applied methods gives reliable CMC values and there is no statistically
significant difference between them. However, for CTin ACN-water mixture
micellar system the integration method for CMC determination is recommended
due to a weak curvature of κ/c plot