Microporous Polymelamine Framework Functionalized with Re(I) Tricarbonyl Complexes for CO2 Absorption and Reduction

A mixture of polymeric complexes based on the reaction between Re(CO)₅Cl and the porous polymeric network coming from the coupling of melamine and benzene-1,3,5-tricarboxaldehyde was obtained and characterized by FTIR, NMR, SEM, XPS, ICP, XRD, and cyclic voltammetry (CV). The formed rhenium-based porous hybrid material reveals a noticeable capability of CO₂ absorption. The gas absorption amount measured at 295 K was close to 44 cm³/g at 1 atm. An interesting catalytic activity for CO₂ reduction reaction (CO₂RR) is observed, resulting in a turn over-number (TON) close to 6.3 under 80 min of test at -1.8 V vs. Ag/AgCl in a TBAPF₆ 0.1 M ACN solution. A possible use as filler in membranes or columns can be envisaged.

Electrically Driven Artificial Muscles Using Novel Polysiloxane Elastomers Modified with Nitroaniline Push-Pull Moieties

The synthesis of novel dielectric elastomers that show a muscle-like actuation when exposed to a low electric field represents a major challenge in materials science. Silicone elastomers modified with polar side groups are among the most attractive dielectrics for such a purpose because of their high polarizability over a wide temperature and frequency range. Nitroaniline (NA) has a strong dipole moment, and therefore, its incorporation into silicone networks should allow the formation of elastomers with increased dielectric permittivity. However, incorporation of a large amount of NA into silicone needed to increase the dielectric permittivity is still challenging. In this work, we present the synthesis of polysiloxane elastomers modified with a large fraction of the nitroaniline (NA) polar group, following two different synthetic strategies. Both approaches allowed the formation of homogenous elastomers at the molecular level. These yellowish materials have a dielectric permittivity three times higher as compared to the reported NA-modified silicones. Additionally, they have excellent mechanical properties with low viscoelastic losses and a strain at break reaching 300%. Furthermore, the mechanical properties of these elastomers can be easily tuned by the content of cross-linkers used. The developed elastomers are highly stable in electromechanical tests and show an actuation strain of 8% at unprecedentedly low electric fields of 7.5 V/μm. The combination of properties such as high dielectric permittivity, large strain at break, low viscoelastic losses, fast and reversible actuation, and actuation at low electric fields is crucial for the new generation of dielectric elastomer materials that will find their way in applications ranging from artificial muscles, soft robots, sensors, and haptic displays to electronic skin.

Synthesis of novel cyclosiloxane monomers containing push–pull moieties and their anionic ring opening polymerization

The synthesis of three novel tetracyclosiloxane monomers modified either with a nitroaniline (NA) or with a Disperse Red 1 (DR1) push–pull group and their ring opening polymerization reaction in the presence of tetramethylammonium hydroxide are presented. The prepared monomers and polymers were characterized by different spectral methods and gel permeation chromatography. For the crystalline monomers, the structures were further proven by single crystal X-ray diffraction. Dynamic scanning calorimetry shows that the polymers that carry NA groups have a glass transition temperature (T_g) well below room temperature (RT), while the one that carries DR1 groups melts at 55 °C. The transition temperatures have a strong effect on permittivity as indicated by broadband impedance spectroscopy measurements conducted at different temperatures and frequencies. The polymers modified with NA groups have a high permittivity (maximum value of 17.3) at RT, suggesting the polar groups to be mobile and orientation polarization to be effective. However, the polar groups of the polymer modified with DR1 are frozen and thus cannot contribute to the permittivity via orientation polarization. Consequently, the permittivity is only 8.8 at RT, but increases to 22 above the melting temperature, where the dipoles are mobile. Because of the high dielectric permittivity and rather low T_g, the polymers modified with NA are attractive as active dielectric materials in actuators, capacitors, and stretchable electronics, whereas the polymer modified with DR1 may be of interest in nonlinear optical devices.

The synthesis of polysiloxanes modified with a nitroaniline or with a Disperse Red 1 push–pull group and their dielectric properties are reported.

The Prevalence of The Burnout Syndrome among Population Examined at The Psychiatric Emergency Department for attempted Suicide

Introduction

The intention of this study is to show the frequency of the burnout syndrome among the population seen at psychiatric ER for the most severe complication of the burnout, the suicide attempt.

Objective

(a) To demonstrate the frequency of burnout among the population examined at psychiatric ER for suicide attempt.

(b) To establish a correlation between the frequency of burnout and:

– the socio-demographic characteristics;

– the psychiatric follow-up;

– the type of personality found.

Methods

Descriptive study on a sample of 92 patients examined at psychiatric ER between 01/02/2014 and 01/06/2014 after a suicide attempt, seen by a single doctor. The patients received the Maslach Burnout inventory (MBI).

Results

The frequency of burnout among the population consulted for suicide attempts is 8.7%. The limitations of this study were: the use of MBI questionnaire only by one doctor and a collection of data carried on a certain period of time.

I managed to characterize the population seen after the suicide attempt induced by the burnout: 88% women; 25% foreign population working in a context with many responsibilities; the predominance of obsessive personality – 50%, followed by anxious personality type – 25%; the suicide attempt was done by a population without psychiatric history and without psychiatric follow-up – 75%; the studied population is divided between patients working in a high responsibility environment – 36% and patients working in the social or the public environment – 63%.

Eighty-eight percent of patients were brought in after their first suicide attempt.

Conclusion

Despite the fact that until now a unanimous definition has not been formulated on the CIM-10, the burnout syndrome is one of the most popular disorders.

The problematic is real, considering that this syndrome, which starts with a psychological distress, can escalade to a self-aggressive behaviour.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Organic–inorganic hybrid nanomaterials based on inorganic oxides and a mesomorphic polyazomethine

Organic–inorganic hybrid materials have been obtained by impregnating a mesomorphic polyazomethine into a porous inorganic matrix of zinc oxide (ZnO), tin dioxide (SnO2), or mixed ZnO/SnO2. The porous inorganic matrix has been obtained by magnetron sputtering technique and proved a very high crystallinity degree. The resulting hybrid materials were characterized from morphological and optical points of view by scanning electron microscopy, atomic force microscopy, and ultraviolet-visible and photoluminescence spectroscopy. The inorganic matrix itself exhibited a highly rough surface, which became smoother after polymer impregnation, indicating its complete coverage. The violet emission of the separate inorganic and organic components turned into a blue and green light emission, respectively, of the hybrid materials, suggesting the possibility to modulate the color of emitted light by the simple choice of the inorganic matrix. Considerations with regard of interface phenomena that prompted the photophysical changes of the hybrid materials were done.