Differential scanning calorimetry and thermally stimulated depolarization currents study on the molecular dynamics in amorphous fenofibrate

2016 ◽  
Vol 623 ◽  
pp. 29-35 ◽  
Author(s):  
Hermínio P. Diogo ◽  
Maria Teresa Viciosa ◽  
Joaquim J. Moura Ramos
Keyword(s):  
Molecular Dynamics ◽  
Differential Scanning Calorimetry ◽  
Scanning Calorimetry ◽  
Thermally Stimulated Depolarization

THERMALLY STIMULATED DEPOLARIZATION CURRENTS AND OPTICAL TRANSMISSION STUDIES ON A 3,4-DICYANOTHIOPHENE-BASED BENT-ROD LIQUID CRYSTAL

2002 ◽  
Vol 16 (13) ◽  
pp. 473-483 ◽  
Author(s):  
CONSTANTIN ROSU ◽  
DOINA MANAILA-MAXIMEAN ◽  
ALEXANDER J. PARASKOS
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Optical Transmission ◽  
Space Charge Polarization ◽  
Scanning Calorimetry ◽  
Conduction Mechanisms ◽  
Transmission Studies ◽  
Thermally Stimulated Depolarization

We study the phase transitions on LC 3,4-Dicyano-2,5-bis[4-(octyloxy)phenylethynyl]-thiophene by the thermally stimulated depolarization currents method and by differential scanning calorimetry. Analyzing the experimental data, information regarding the conduction mechanisms for each mesophase are obtained. The results are consistent with the existence of a space charge polarization where the trapped charges are characterized by a slow retrapping probability. We measure the value of the activation energy, specific to the conduction process. We analyze the influence of the polarizing field on the optical transmission measured simultaneously with the thermally stimulated depolarization currents.

scholarly journals The Two Faces of the Liquid Ordered Phase

2021 ◽  
Author(s):  
Itay Schachter ◽  
Riku Paananen ◽  
Balazs Fabian ◽  
Piotr Jurkiewicz ◽  
Matti Javanainen
Keyword(s):  
Molecular Dynamics ◽  
Differential Scanning Calorimetry ◽  
Low Temperatures ◽  
High Mobility ◽  
Membrane Properties ◽  
Scanning Calorimetry ◽  
Lipid Mixtures ◽  
Liquid Ordered ◽  
Raft Domains ◽  
Dynamics Simulations

The coexistence of liquid ordered Lo and liquid disordered Ld phases in synthetic and plasma membrane-derived vesicles serves as a model for biomembrane heterogeneity. However, the connection between the structures of microscopic phases present in vesicles at low temperatures and the tiny ordered "raft" domains of biomembranes at body temperature is unclear. To study the Lo phase structure across temperatures, we performed atomistic molecular dynamics simulations, differential scanning calorimetry, and fluorescence spectroscopy on the Lo phase in binary and ternary lipid mixtures. Our results reveal an Lo phase with highly ordered and hexagonally packed clusters of saturated lipid chains at low temperatures. These clusters melt upon heating, and numerous membrane properties reflect this transition as two regimes with different temperature dependence. Still, the transition between the regimes is continuous, and they both match the description of the Lo phase with high order and relatively high mobility. Our findings question the use of vesicles displaying Lo–Ld coexistence as models for heterogeneity in cellular membranes, as they likely correspond to different molecular organizations.

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