Surface crystallization of ionic liquid crystals

The evidence for surface crystallization in ionic liquids is scarce. The existing reports seem to be contradictory as for its driving forces, since in the two compounds investigated in the literature, the contribution of coloumbic and van der Waals forces is very different. In this work 1-dodecyl-3- methylimidazolium tetrafluoroborate was studied and its surface crystallization characterized by surface tension, ellipsometry and optical microscopy. The results obtained seem to reconcile previous observations, and it was further shown, using the same techniques, that this phenomenon is prevalent in other ionic liquids. MD simulation results illustrate the different possibilities of organization, providing reasonable models to rationalize the experimental observations.This work was developed with the scope of the project CICECO – Aveiro Institute of Materials, UID/CTM/50011/2019, Associate Laboratory LSRE-LCM, UID/EQU/50020/2019, and of Instituto de Telecomunicaço˜es/IT (UID/EEA/50008/2013) – funded by national funds through FCT/MCTES (PIDDAC). M. A. R. M. acknowledges financial support from NORTE-01-0145-FEDER- 000006 – funded by NORTE2020 through PT2020 and ERDF, and P. J. C. acknowledges the FCT for the contract IF/00758/2015. A. R. Bastos from UA is acknowledged for help in the ellipsometry measurements. M. C. C. aknowledges FAPESP (2012/05027-1) and CNPq (310272/2017) for financial support.info:eu-repo/semantics/publishedVersio

Monitoring of Generation and Stability of Droplets in Miniemulsion Polymerizarion Using the Near-Infrared Spectroscopy

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High-Pressure Phase Behavior for Poly(ethylene glycol) and 1,1,1,2-Tetrafluorethane Systems

The development of polymeric systems for drug deliveryhas received attention with the aim of producing new systems as an alternative to conventional drug therapy. The design of new systems for this purpose in a compressed medium requires a knowledge of the phase behavior for the polymeric matrix in the high-pressure fluids. This work reports the phase equilibrium experimental data of binary systems involving poly(ethylene glycol) (PEG) with molecular weights of 1000and 2000 g·mol−1 and 1,1,1,2-tetrafluoroethane (HFA-134a). The experimental data were obtained in a high-pressure variable-volume viewing cell based on the static synthetic method at temperatures from 287.4 to 334.2 K, pressures of up to 29.81 MPa, and a PEG concentration in the range of 1 to 7 wt %. Liquid−liquid equilibrium,liquid−liquid−vapor equilibrium, and, in some cases, solid−liquid equilibrium were observed under the experimental conditions of pressure, temperature, and compositions investigated. The experimental results show that temperature and pressure have significant influences on the solubility of PEG in HFA-134a. The solid-phase formation for the system PEG + HFA-134a, in the range of values investigated for temperature, pressure, and compositions, is influenced by the molecular weight of the polymer.Fil: Oliveira Meneses, Marcela. Universidade Tiradentes. Programa de Pós-Graduação em Engenharia de Processos. Instituto de Tecnologia e Pesquisa; BrasilFil: Dariva, Claudio. Universidade Tiradentes. Programa de Pós-Graduação em Engenharia de Processos. Instituto de Tecnologia e Pesquisa; BrasilFil: Rodrigues Borges, Gustavo. Universidade Tiradentes. Programa de Pós-Graduação em Engenharia de Processos. Instituto de Tecnologia e Pesquisa; BrasilFil: da Rocha, Sandro R. P.. Virginia Commonwealth University; Estados UnidosFil: Zabaloy, Marcelo Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Franceschi, Elton. Universidade Tiradentes. Programa de Pós-Graduação em Engenharia de Processos. Instituto de Tecnologia e Pesquisa; Brasi

Correlations between pulp properties of eucalyptus clones and leaf volatiles using automated solid-phase microextraction

Analysis of biogenic volatile organic compounds (BVOC) of 14 Eucalyptus clones has been performed using an automated headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography (GC)/ion trap mass spectrometry (ITMS) method. Correlations between pulp properties of Eucalyptus clones and the BVOC of their leaf headspaces were studied. The compounds R-terpineol and the sesquiterpene â-eudesmol were positively correlated with S5, a property related to the hemicelluose content in the pulp. Qualitative results obtained with automated HS-SPME were sufficient to group together the same species and related hybrids through cluster analysis and were confirmed through principal component analysis. A preliminary separation of the essential oils of Eucalyptus dunnii through comprehensive two-dimensional gas chromatography (GC × GC) showed ∼580 peaks compared to ∼60 in a typical GC/ITMS first-dimension chromatogram. The potential of HS-SPME coupled to GC × GC to improve the separation of Eucalyptus volatiles and other plant essential oils looks extremely promising for new applications of unsupervised learning methods

<i>Himatanthus bracteatus</i>-Composed In Situ Polymerizable Hydrogel for Wound Healing

The Himatanthus genus presents anti-inflammatory, antioxidant activities, suggesting potential wound-healing properties. This study aimed to develop and analyze the wound-healing properties of a photopolymerizable gelatin-based hydrogel (GelMA) containing an ethanolic extract of Himatanthus bracteatus in a murine model. The extract was obtained under high pressure conditions, incorporated (2%) into the GelMA (GelMA-HB), and physically characterized. The anti-inflammatory activity of the extract was assessed using a carrageenan-induced pleurisy model and the GelMA-HB scarring properties in a wound-healing assay. The extract reduced IL-1β and TNF-α levels (48.5 ± 6.7 and 64.1 ± 4.9 pg/mL) compared to the vehicle (94.4 ± 2.3 pg/mL and 106.3 ± 5.7 pg/mL; p p p p < 0.05). In conclusion, GelMA-HB improved wound healing in rodents, probably by modulating the inflammatory response and myofibroblastic and microvascular differentiation