scholarly journals Polymorphic Phases of Supramolecular Liquid Crystal Complexes Laterally Substituted with Chlorine

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4292
Author(s):  
Fowzia S. Alamro ◽  
Omaima A. Alhaddad ◽  
Magdi M. Naoum ◽  
Hoda A. Ahmed
Keyword(s):  
Chlorine Atom ◽  
Supramolecular Complexes ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Smectic A ◽  
Smectic C ◽  
Ft Ir ◽  
The Impact ◽  
Cl Atom ◽  
Mesomorphic Properties

New supramolecular complexes, based on H-bonding interactions between 4-(pyridin-4-yl) azo-(2-chlorophenyl) 4-alkoxybenzoates (Bn) and 4-[(4-(n-hexyloxy)phenylimino)methyl]benzoic acid (A6), were prepared and their thermal and mesomorphic properties investigated via differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FT-IR) in order to confirm their H-bonding interactions. The mesophase behavior of each mixture was examined by DSC and polarized optical microscopy (POM). According to the findings of the study, in all of the designed mixtures, the introduction of laterally polar chlorine atom to the supramolecular complexes produces polymorphic compounds possessing smectic A, smectic C and nematic mesophases, in addition, all products have low melting transitions. Thermal stabilities of the associated phases depend on the position and orientation of the lateral polar Cl− atom as well as the length of terminal flexible alkoxy chain. Comparisons were made between the present lateral Cl− complexes and previously investigated laterally-neat complexes in order to investigate the impact of the addition, nature and orientation of polar substituent on the mesomorphic behavior. The investigations revealed that, the polarity and mesomeric nature of inserted lateral substituent into the base component play an essential role in affecting their mesomorphic properties. Furthermore, for current complexes, induced polymorphic phases have been found by introducing the chlorine atom.

scholarly journals Induced Phases of New H-bonded Supramolecular Liquid Crystal Complexes; Mesomorphic and Geometrical Estimation

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1549 ◽  
Author(s):  
Rua B. Alnoman ◽  
Hoda A. Ahmed ◽  
Mohamed Hagar ◽  
Khulood A. Abu Al-Ola ◽  
Bedor Sh. Alrefay ◽  
...  
Keyword(s):  
Density Functional ◽  
Aromatic Rings ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Smectic C ◽  
Computational Calculations ◽  
Theoretical Predictions ◽  
Temperature Ranges ◽  
Homo And Lumo ◽  
Ft Ir

New five rings architecture of 1:1 supramolecular hydrogen bonded (H-bonded) complexes were formed between 4-(2-(pyridin-4-yl)diazenyl-3-methylphenyl 4-alkoxybenzoates and 4-n-alkoxyphenyliminobenzoic acids. Mesomorphic and optical behaviors of three systems designed complexes were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). H-bonded interactions were confirmed via FT-IR spectroscopy. Computational calculations were carried out by density functional theory (DFT) estimation for all formed complexes. Experimental evaluations were correlated with the theoretical predictions and results revealed that, all prepared complexes possessing enantiotropic tri-mesophases with induced smectic C (SmC) and nematic temperature ranges. Moreover, DFT predicted for all formed supramolecular complexes possessing a non-linear bent geometry. Moreover, the π–π stacking of the aromatic rings plays an important role in the mesomorphic properties and thermal stabilities of observed phases. The energy changes between frontier molecular orbitals (HOMO and LUMO) and the molecular electrostatic potential (MEP) of the designed complexes were discussed and related to the experimental results.

scholarly journals Influence of spacer chain lengths and polar terminal groups on the mesomorphic properties of tethered 5-phenylpyrimidines

2009 ◽  
Vol 5 ◽  
Author(s):  
Gundula F Starkulla ◽  
Elisabeth Kapatsina ◽  
Angelika Baro ◽  
Frank Giesselmann ◽  
Stefan Tussetschläger ◽  
...  
Keyword(s):  
Terminal Group ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Maximum Phase ◽  
X Ray ◽  
Smectic A ◽  
Polar Groups ◽  
Chain Lengths ◽  
Mesomorphic Properties ◽  
Phase Width

Based on 5-(4-hydroxyphenyl)-2-octylpyrimidine 8, 5-phenylpyrimidine derivatives 3–7, 9 with different spacer chain lengths (C2 up to C6) and different terminal polar groups (Br, Cl, N3, OH, CN) were synthesized by etherification and nucleophilic substitution. The mesomorphic behaviour of these compounds was investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (WAXS and SAXS) and revealed smectic A mesophases for bromides, chlorides and azides 3, 4 and 6. For these compounds a maximum phase width was observed for the C5 spacer regardless of the terminal group, whereas the hydroxy- and cyano-substituted derivatives 5 and 7, respectively, were non mesomorphic and showed only melting transitions.

A New Modifier Prepared and it’s Applied in High-Density Polyethylene/Anhydrite Composites

2011 ◽  
Vol 415-417 ◽  
pp. 390-394
Author(s):  
Shao Hui Wang
Keyword(s):  
High Density Polyethylene ◽  
Bending Strength ◽  
Crystallization Rate ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Powder Particles ◽  
Ft Ir ◽  
Anchoring Group ◽  
The Impact

A new Modifier with Silicon radicals as anchoring group and poly(butyl acrylate) as solvatable chain was synthesized and its effect on the properties of HDPE/Anhydrite composites was investigated in this paper. Fourier transmission infrared spectroscopy (FT-IR) results show that the modifier react on the Anhydrite powder particles surface and the modified Anhydrite powder particles particles. compared with that of HDPE/Anhydrite (filled with same non-modified fraction), The impact strength, tensile strength, bending strength and Young’s modulus of modified HDPE/Anhydrite composites increased about 36.6%, 7.5%, 15.6% and 34% respectively. Based on surface analysis by scanning electron microscope (SEM), the Anhydrite powder particles buried well in HDPE matrix when Anhydrite powder particles was coated with the YB modifier. It was found that Anhydrite powder particles significantly increased the crystallization temperature and crystallization rate of HDPE by differential scanning calorimetry (DSC). At same time, through the X-ray diffraction (XRD) found the addition of the YB modifier modified Anhydrite powder particles can not change the formation of crystal HDPE, but can reduce the crystallite size.

Trimesic Acid-Based Star Mesogens with Flexible Spacer: Synthesis and Mesophase Characterization

2012 ◽  
Vol 65 (10) ◽  
pp. 1426 ◽  
Author(s):  
A. Shanavas ◽  
T. Narasimhaswamy ◽  
A. Sultan Nasar
Keyword(s):  
13C Nmr Spectroscopy ◽  
Steric Repulsion ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Analysis Techniques ◽  
Trimesic Acid ◽  
Smectic A ◽  
Flexible Spacer ◽  
Ft Ir ◽  
Alkoxy Groups

A series of trimesic acid-based star mesogens containing an octamethylenoxy spacer and two-ring containing side arms with terminal alkoxy groups were synthesised by a divergent approach. A structurally similar mesogen containing a three-ring side arm was also synthesised. All the mesogens and intermediates were characterised thoroughly using FT-IR, 1H NMR, 13C NMR spectroscopy, and elemental analysis techniques. The mesophase characteristics were identified by hot stage optical polarising microscopy (HOPM) and differential scanning calorimetry (DSC), while X-ray was used to confirm the existence of a smectic A (SA) phase. The HOPM and DSC results revealed the presence of rich polymesomorphism in the star mesogens. The dominance of a SA phase in the series is attributed to the steric repulsion associated with steric asymmetry. The change of the side arm from two rings to three rings was found to increase the mesophase stability.

Synthesis and Phase Behaviors of New Heterocyclic Liquid Crystals: Nematic and Smectic Properties

2014 ◽  
Vol 699 ◽  
pp. 233-238 ◽  
Author(s):  
Kok Leei Foo ◽  
Sie Tiong Ha
Keyword(s):  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Phase Behaviour ◽  
Scanning Calorimetry ◽  
Smectic A ◽  
Lower Member ◽  
Smectic A Phase ◽  
Phase Behaviors ◽  
New Compounds ◽  
Mesomorphic Properties

A series of new rod-shaped liquid crystal, 6-methoxy-2-(4-alkyloxybenzylidenamino) benzothiazoles possessingeven numbers of carbon atoms at the alkyloxy chain (CnH2n+1O-, n = 10, 12, 14, 16, 18) are prepared and characterized. The phase behaviour of these new compounds was studied by differential scanning calorimetry and polarising optical microscopy. All members exhibited mesophase. Influence of alkyl chain length on the mesomorphic properties was studied. Enantiotropic nematic phase was identified in all the members except for n = 18. Lower member (n = 10) exhibited monotropic (metastable) smectic A phase. The enantiotropic smectic A phase was observed fromn-dodecyloxy derivatives onward to the last homologous synthesized.

scholarly journals Effect of Polythiophene Content on Thermomechanical Properties of Electroconductive Composites

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2476
Author(s):  
Katarzyna Bednarczyk ◽  
Tomasz Kukulski ◽  
Ryszard Fryczkowski ◽  
Ewa Schab-Balcerzak ◽  
Marcin Libera
Keyword(s):  
Organic Solar Cells ◽  
Polyamide 6 ◽  
Thermomechanical Properties ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
Mechanical And Electrical Properties ◽  
Ft Ir ◽  
Conductive Properties ◽  
The Impact ◽  
Properties Of Composites

The thermal, mechanical and electrical properties of polymeric composites combined using polythiophene (PT) dopped by FeCl3 and polyamide 6 (PA), in the aspect of conductive constructive elements for organic solar cells, depend on the molecular structure and morphology of materials as well as the method of preparing the species. This study was focused on disclosing the impact of the polythiophene content on properties of electrospun fibers. The elements for investigation were prepared using electrospinning applying two substrates. The study revealed the impact of the substrate on the conductive properties of composites. In this study composites exhibited good thermal stability, with T5 values in the range of 230–268 °C that increased with increasing PT content. The prepared composites exhibited comparable PA Tg values, which indicates their suitability for processing. Instrumental analysis of polymers and composites was carried out using Fourier Transform Infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM).

scholarly journals Effect of Flexible Chain on Mesomorphic Properties of Alkyloxy Substituted 4-Chloroazobenzene Liquid Crystals

2021 ◽  
Vol 33 (5) ◽  
pp. 1159-1164
Author(s):  
Kamruzzaman ◽  
Roushown Ali ◽  
Rabiul Karim ◽  
Samiul Islam Chowdhury ◽  
Tariqul Hasan
Keyword(s):  
Liquid Crystals ◽  
Optical Microscope ◽  
Scanning Calorimetry ◽  
Flexible Chain ◽  
Spacer Length ◽  
Smectic A ◽  
Alkyl Bromides ◽  
Dsc Analyses ◽  
Azobenzene Derivatives ◽  
Mesomorphic Properties

Three rod-shaped alkyloxy substituted 4-chloroazobenzene liquid crystals, 1-(4-chlorophenyl)-2-[4- (alkyloxy)phenyl]diazene (hexayl, octyl and nonyl as flexible oxyalkyl chain) have been synthesized by diazotization of p-chloroaniline with phenol and subsequently performed etherification reaction with different alkyl bromides. The structures of the substituted 4-chloroazobenzene liquid crystals have been characterized by spectroscopic methods. The mesomorphic properties of the liquid crystals were examined by polarizing optical microscope (POM) and differential scanning calorimetry (DSC). All the oxyalkyl homologues of chloro substituted azobenzene showed enantiotropic smectic A (SmA) mesophase, which was understood clearly by the texture of the compounds employing polarizing optical microscope (POM) analysis. During heating scan in DSC analyses melting points, SmA-isotropic temperature and enthalphy changes associated with SmA-isotropic transition showed a remarkable impact on the spacer length of 4-chloro azobenzene derivatives.

scholarly journals Synthesis and characterization of linear and crosslinked polymers with the addition of DMSPS

2019 ◽  
Vol 73 (1) ◽  
pp. 1
Author(s):  
Karolina Fila ◽  
Beata Podkościelna
Keyword(s):  
Spectroscopic Analysis ◽  
Bulk Polymerization ◽  
Synthesis And Characterization ◽  
Scanning Calorimetry ◽  
Chemical Structures ◽  
Hardness Tests ◽  
Ft Ir ◽  
The Impact ◽  
Sulfur Containing

<p>The aim of this research was the synthesis of polymers with the addition of S,S'-thiodi-4,1-phenylene bis(thiomethacrylate) (DMSPS) by bulk polymerization. Styrene (St), divinylbenzene (DVB) and ethylene glycol dimethacrylate (EGDMA) were used for the copolymerization as main monomers. The chemical structures of sulfur-containing polymers were confirmed by the spectroscopic analysis (ATR/FT-IR). In order to determine the impact of the sulfur derivative (DMSPS) addition on thermal properties of the obtained copolymers, differential scanning calorimetry (DSC) was performed. The hardness tests of the obtained copolymers were also applied using a Shore durometer.</p>

Synthesis of Ferroelectric Liquid Crystalline Polymers by Ring Opening Polymerization

1996 ◽  
Vol 425 ◽  
Author(s):  
C. S. Hsu ◽  
C. J. Lee
Keyword(s):  
Ring Opening ◽  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Ring Opening Polymerization ◽  
Side Chain ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystalline Polymers ◽  
Smectic A ◽  
Smectic C

AbstractThe synthesis of two series of side-chain liquid crystalline polyoxetanes and polyoxiranes containing 4-alkanyloxybiphenyl-4′ -yl (2S,3S)-2-chloro-3-methylvalerate side groups is presented. Differential scanning calorimetry, polarizing optical microscopy, and X-ray diffractometry reveal smectic mesomorphism for all obtained polymers. Most of the prepared polyoxetanes present smectic A and chiral smectic C phases. The polyoxetane containing tweleve methylene units in the spacer is the only one showing two enantiotropic smectic A and B phases. All of the obtained polyoxiranes display two enantiotropic smectic A and B phases. Although the polyoxetane and polyoxirane backbones are more flexible than the polymethacrylate backbone, side-chain crystallization do not occur in any of the synthesized polymers.

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