Characterization of Main-Chain Liquid Crystal Elastomers by Using Differential Scanning Calorimetry (DSC) Method

2015 ◽  
Vol 1123 ◽  
pp. 69-72 ◽  
Author(s):  
Supardi ◽  
Y. Yusuf ◽  
Harsoyo
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Basic Principle ◽  
Main Chain ◽  
Scanning Calorimetry ◽  
Mechanical Effects ◽  
Liquid Crystal Elastomers ◽  
Dsc Method

We performed an experiment to characterize the four samples of main chain liquid crystal elastomers (MCLCEs) by using differential scanning calorimetry (DSC) method. Basic principle of this method is that difference in the amount of heat required to increase the temperature of the sample and reference is measured as a function of temperature. The temperature between the sample and reference is maintained nearly the same throughout the experiment. There were four samples with different concentrations of crosslinker we have taken, namely 8%, 12%, 14%, and 16%. The results showed that the phase transition from nematic to isotropic obtained by this method had correlation with their thermo-mechanical effects.

Dependence of Phase Transition of a Bent-Core Liquid Crystal on the Heating Rate

2010 ◽  
Vol 663-665 ◽  
pp. 787-790 ◽  
Author(s):  
Qing Lan Ma ◽  
Yuan Ming Huang
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Optical Microscopy ◽  
Heating Rate ◽  
Broad Peak ◽  
Crystal Phase ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Crystal Compound

A bent-core liquid crystal compound N,N-bis (4-propoxybenzylidene)benzene- 1,3-diamine was synthesized. Phase transition properties of the synthesized compound with the deferent heating rate were characterized with differential scanning calorimetry and polarized optical microscopy. , respectively. Our results demonstrated that the bent-core compound exhibited the completely undivided multi-phases in heating-rate ranges from 1oC/min to 6oC/min while it showed a broad-peak crystal phase in higher heating-rate ranges of 7-10oC/min for the first heating.

Synthesis and Mesomorphic Properties of a Series of Cholesteric Liquid Crystals

2010 ◽  
Vol 663-665 ◽  
pp. 759-762 ◽  
Author(s):  
Qing Lan Ma ◽  
Yuan Ming Huang
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Optical Microscopy ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Phase Transition Temperatures ◽  
Second Category ◽  
Mesomorphic Properties

A series of cholesterol liquid crystal compounds was synthesized. Phase-transition temperatures and mesomorphic textures of these synthesized compounds were characterized with differential scanning calorimetry and polarized optical microscopy, respectively. In these molecules the terminal ester chains CnH2n-1COO-, where n was the number of carbon atoms in the terminal ester chains, were linked to the cholesterol core. All of the synthesized cholesterol compounds exhibited mesophases for the first heating. However, as temperature decreased from their clearing points, their micrographs can also be divided into two categories, the first category exhibits branch-like mesophase textures for n in the range of 1-10 while the second category exhibits branch-like crystal textures for n in the range of 11-18.

Experimental Studies of Thermo-Induced Mechanical Effects in the Main-Chain Liquid Crystal Elastomers

2014 ◽  
Vol 896 ◽  
pp. 322-326 ◽  
Author(s):  
Supardi ◽  
Harsojo ◽  
Yusril Yusuf
Keyword(s):  
Liquid Crystal ◽  
Critical Temperature ◽  
Main Chain ◽  
Experimental Studies ◽  
Artificial Muscles ◽  
Direction Parallel ◽  
Mechanical Effects ◽  
Liquid Crystal Elastomers ◽  
Heating Up ◽  
Contraction And Expansion

Liquid crystal elastomers (LCEs), either side-chain LCEs (SCLCEs) or main-chain LCEs (MCLCEs), possess a combination of LC and elastic properties, and are expected to be used as artificial muscles. We experimentally investigated the thermo-induced mechanical effects showed by MCLCEs with four different crosslinker concentrations, i.e., 8%, 12%, 14% and 16%. The samples were heated up to the critical temperature and the images were recorded. The samples made the contraction in direction parallel to the director and the expansion in direction perpendicular to the director. Drastic changes occured when approaching the critical temperature, the greater the crosslinkers concentration the bigger the maximum contraction and expansion. The shape anisotropy expression showed that heating up to the critical temperature caused the system no longer in anisotropic state.

Novel isochoric measurement of the onset of vapor–liquid phase transition using differential scanning calorimetry

2018 ◽  
Vol 20 (41) ◽  
pp. 26241-26248 ◽  
Author(s):  
Xingdong Qiu ◽  
Sugata P. Tan ◽  
Morteza Dejam ◽  
Hertanto Adidharma
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Phase ◽  
Dew Point ◽  
Gas Mixture ◽  
Scanning Calorimetry ◽  
Liquid Phase Transition ◽  
Dsc Method ◽  
Vapor Liquid

Dew point measurements of methane/ethane gas mixture using isochoric DSC method.

Synthesis and Mesomorphic Properties of Three-Benzene-Ring Containing Bent-Core Liquid Crystal 1,3-Phenylene-bis[4-(nonylcarboyloxyl) benzylideneamine]

2010 ◽  
Vol 428-429 ◽  
pp. 79-82 ◽  
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Benzene Ring ◽  
Cyclic Heating ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Heating And Cooling ◽  
Phase Transition Temperatures ◽  
Mesomorphic Properties

A bent-core compound with three benzene-ring cores 1,3-phenylene-bis [4-(nonylcarboyloxyl)benzyl ideneamine] was synthesized. Its mesomorphic properties were characterized with differential scanning calorimetry and polarized optical microscopy, respectively. This kind of bent-core compound exhibited mesophases in the temperature range of 155-185oC for the first cooling but cyclic heating and cooling could lower the phase transition temperatures for this bent-core liquid crystal. Our results demonstrated that bent-core molecules with three benzene-ring cores can also form mesophases as those five benzene-ring containing bent-core molecules do.

scholarly journals Thermal Properties of Lignocellulose Pellets

2017 ◽  
Vol 25 (40) ◽  
pp. 83-90
Author(s):  
Igor Wachter ◽  
Siegfried Hirle ◽  
Karol Balog
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Reaction Enthalpy ◽  
Wood Pellets ◽  
Scanning Calorimetry ◽  
Wood Pellet ◽  
Exothermic Reactions ◽  
Enthalpy Changes ◽  
Dsc Method

Abstract This article deals with the characterization of biomass pellets using Differential Scanning Calorimetry. We used three types of industrially produced and commercially available pellets as samples: wood pellets containing grass, wood pellet containing bark and wood pellets without bark. Each of the samples were examined using the DSC method. Based on the measurements in atmosphere of air and nitrogen temperature, the changes caused by thermal degradation of various kinds of test fuels were observed. Subsequently, limits of exothermic processes, reaction enthalpy changes and the temperature at which exothermic reactions reached peaks were determined.

scholarly journals Characterization of polymer-liquid crystal blends

2001 ◽  
Vol 66 (3) ◽  
pp. 153-159 ◽  
Author(s):  
Daniela Filip ◽  
Cristofor Simionescu ◽  
Doina Macocinschi
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
The Other ◽  
Diphenylmethane Diisocyanate ◽  
Solution Casting ◽  
Scanning Calorimetry ◽  
Crystalline Polymers ◽  
Cholesteryl Palmitate ◽  
Polymer Liquid Crystal

Blends of semi-crystalline polymers (polyethylene adipate and two poly(ester-urethane) s) with liquid crystal cholesteryl palmitate with different compositions were prepared by solution casting. One of the poly(ester-urethane)s was based on 2,4-tolylene diisocyanate (TDI) and the other one on 4,4?-diphenylmethane diisocyanate (MDI). The miscibility and phase transition were investigated over the whole range of concentration by differential scanning calorimetry and polarizing optical microscopy.

scholarly journals Preparation and Characterization of Large Unilamellar Vesicles Mixed With Trimethylchitosan (TMC): The Effect of Polyelectrolyte Concentration

2018 ◽  
Vol 12 (1) ◽  
pp. 134-139
Author(s):  
S.M. Van Der Merwe ◽  
N. Bouropoulos ◽  
D.A. Katsamenis ◽  
O.L. Lampou ◽  
D.G. Fatouros
Keyword(s):  
Phase Transition ◽  
Nuclear Magnetic Resonance ◽  
Differential Scanning Calorimetry ◽  
Unilamellar Vesicles ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Mucosal Delivery ◽  
Large Unilamellar Vesicles ◽  
Potential Use

Background: The effect of different concentrations of the absorption enhancer Trimethyl Chitosan (TMC) to the physicochemical properties of Large Unilamellar Vesicles (LUV) comprised of L-a-Phospahtidyl Choline (PC) were investigated in the current study. Methods: The Degree of Quartenization (DQ) of trimethylchitosan was assessed with nuclear magnetic resonance (1H NMR). The vesicles were characterized by means of Dynamic Light Scattering (DLS), ζ-potential, Differential Scanning Calorimetry (DSC) and Contact Angle Goniometry (CAG) measurements. Results: The data showed that the surface charge of the PC liposomes was significantly altered as a function of the TMC concentration, giving evidence of presence of the polyelectrolyte to the liposome’s membrane. Varying the concentration of TMC affected the phase Transition Temperature (Tm) of the lipid, verifying the miscibility of the polyelectrolyte with the lipid bilayer. The association of the polymer with the liposomes was related to the amount of the polyelectrolyte present, reflecting changes to the wettability of the dispersion as measured by CAG. Conclusion: The results demonstrated that presence of TMC significantly modified the physical properties of liposomes. Such systems might have a potential use for mucosal delivery (e.g. nasal route of administration).

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