Untersuchungen der elektrischen Leitfähigkeit homologer 4,4′-Di-n-alkyloxy-azoxybenzole im nematischen Phasenbereich / Investigation of the Electric Conductivity of Homologous 4,4′-Di-n-alkoxyazoxybenzenes in their Nematic Phase

1975 ◽  
Vol 30 (3) ◽  
pp. 316-322 ◽  
Author(s):  
G. Heppke ◽  
F. Schneider
Keyword(s):  
Electric Conductivity ◽  
Chain Length ◽  
Nematic Phase ◽  
Alkyl Chain ◽  
Electrolyte Concentration ◽  
Alkyl Chain Length ◽  
Effect Of Temperature ◽  
Alkyl Chains ◽  
Long Chains

The effect of temperature and concentration of the added electrolyte tetrabutylammoniumpicrate on the electric conductivity of homologous 4,4′-di-n-alkoxyazoxybenzenes (C1 to C8) in their nematic phase is investigated. In general an increase of the alkyl chain length results in a decrease of the ratio of anisotropy x∥/x⊥. At the lowest temperature of the nematic phase values between 1,6 (C2) and 0,45 (C8) are obtained. This behaviour can be explained by the formation of cybotactic groups with a smectic structure. Increasing the electrolyte concentration reduces the ratio of anisotropy for short alkyl chains, whereas for long chains the ratio rapidly increases.

Untersuchung der elektrischen Leitfähigkeit homologer N-(4-n-Alkyloxybenzyliden)-4'-n-butylaniline im nematischen und smektischen Phasenbereich / Investigation of the Electrical Conductivity of Homologous N-(4-n-alkoxybenzylidene)-4'-nbutylanilines in the Nematic and Smectic Phases

1976 ◽  
Vol 31 (12) ◽  
pp. 1700-1706 ◽  
Author(s):  
G. Heppke ◽  
F. Schneider ◽  
A. Sterzl
Keyword(s):  
Electrical Conductivity ◽  
Chain Length ◽  
Nematic Phase ◽  
Alkyl Chain ◽  
Electrolyte Concentration ◽  
Alkyl Chain Length ◽  
Anisotropy Ratio ◽  
Concentration Effects ◽  
Smectic Phases ◽  
Nematic Phases

Abstract Investigation The electrical conductivity of the first eight homologous N-(4-n-alkoxybenzylidene)-4'-n-butylanilines is investigated in the isotropic, nematic and smectic phases using the electrolyte tetra-butylammonium picrate. The anisotropy ratio of the electrical conductivity shows pretransition behaviour in the nematic phases close to the transition to the smectic phases. This behaviour be-comes more distinct with increasing alkyl chain length of the liquid crystals. In the nematic phase of 40·4 an anisotropy ratio of V = 0.55 is determined at the lowest electrolyte concentration. Values of about V=0.05 were found in the smectic phases of several homologues. In the nematic phase, an increase of the electrolyte concentration effects an increase of the anisotropy ratio. This effect is systematically enhanced with increasing alkyl chain length.

Understanding the effect of alkyl chains of gemini cations on the physicochemical and cellular properties of polyurethane micelles

2018 ◽  
Vol 6 (7) ◽  
pp. 1899-1907 ◽  
Author(s):  
Zhicheng Pan ◽  
Danxuan Fang ◽  
Yuanqing Song ◽  
Nijia Song ◽  
Mingming Ding ◽  
...  
Keyword(s):  
Surface Charge ◽  
Chain Length ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Absorption Properties ◽  
Protein Absorption ◽  
Alkyl Chains

The alteration of the gemini alkyl chain length could affect the surface charge exposure, stability, and the protein absorption properties of nanocarriers.

Biological Activity of New N-Oxides of Tertiary Amines

2006 ◽  
Vol 61 (9-10) ◽  
pp. 715-720 ◽  
Author(s):  
Halina Kleszczyńska ◽  
Krzysztof Bielecki ◽  
Janusz Sarapuk ◽  
Dorota Bonarska-Kujawa ◽  
Hanna Pruchnik ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Chain Length ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Resting Membrane Potential ◽  
Tertiary Amines ◽  
Alkyl Chains ◽  
Main Transition ◽  
Chain Compounds ◽  
Potassium Leakage

AbstractPotential biological properties of newly synthesized single and double alkyl chain N-oxides of tertiary amines (NTA) were studied. Individual compounds in each of the series had alkyl chains of different length. Various experiments were performed to determine a mechanism of the interaction between NTA and model and biological membranes. These were measurements of hemolytic efficiencies of NTA (pig erythrocytes), their influence on the transition temperatures (DPPC liposomes), on potassium leakage from cucumber, its growth and chlorophyll content (Cucumis sativus cv. Krak F1), and on the resting membrane potential in alga cells (Nitellopsis obtusa). Also, prevention of erythrocyte membrane lipid oxidation induced by UV irradiation was studied. Potential antioxidative properties of NTA were additionally tested in radical chromogen (ABTS●+) experiments in which antioxidative efficiencies of NTA were compared to that of the standard antioxidant Trolox. It was found that NTA readily interacted with erythrocyte membranes. Their hemolyzing efficiency increased with the alkyl chain length. Slightly more intensive interaction was found for double alkyl chain compounds. Similar results were obtained in DSC experiments, where incorporation of NTA into liposomal membranes shifted the main transition temperatures and caused a broadening of the main transition peaks depending on the alkyl chain length. Double alkyl chain compounds were also found more efficiently influencing the growth of cucumber. Influence of NTA on the resting membrane potential of algae cells was not quite following the alkyl chain length rule found in erythrocyte and liposome experiments. Also potassium leakage and chlorophyll content determined in physiological experiments were not following the increase of lipophilicity of compounds. Most efficiently influencing those parameters were NTA having shorter alkyl chains, and efficiencies of single alkyl chain compounds were evidently stronger. Both methods used to test the antioxidative properties of NTA showed that they depended on the alkyl chain lengths of compounds within each series, but double alkyl chain ones exhibited markedly greater efficiency.

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