Characterization and Minimization of Block Copolypeptide Vesicle Cytotoxicity Using Different Hydrophobic Chain Lengths

2013 ◽  
Vol 214 (9) ◽  
pp. 994-999 ◽  
Author(s):  
Uh-Joo Choe ◽  
April R. Rodriguez ◽  
Zhibo Li ◽  
Sergey Boyarskiy ◽  
Timothy J. Deming ◽  
...  
Keyword(s):  
Hydrophobic Chain ◽  
Block Copolypeptide ◽  
Chain Lengths

scholarly journals Adsorption and Corrosion Performance of New Cationic Gemini Surfactants Derivatives of Fatty Amido Ethyl Aminium Chloride with Ester Spacer for Mild Steel in Acidic Solutions

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2790
Author(s):  
Nashwa S. Bin-Hudayb ◽  
Entsar E. Badr ◽  
M.A. Hegazy
Keyword(s):  
Mild Steel ◽  
Gemini Surfactants ◽  
Ester Group ◽  
Charge Transfer Resistance ◽  
Maximum Efficiency ◽  
Transfer Resistance ◽  
Cationic Gemini Surfactants ◽  
Hydrophobic Chain ◽  
Inhibition Performance ◽  
Chain Lengths

Three new cationic gemini surfactants with ester spacer type 2-2′-(ethane-1,2-diyl bis(oxy)) bis(N-(2-alkanamidoethyl)-N,N-dimethyl-2-oxoethan-1-aminium)) dichloride) (CGSES12, CGSES14 and CGSES16), based on N,N-dimethyl fatty amido ethylamine, were produced. These gemini quaternary ammonium salts were synthesized using a three-step reaction method, starting from th/e condensation of the fatty acid chloride (RCOCl) of various hydrophobic chain lengths (R, C11H23, C13H27, C15H31) with N,N-dimethyl ethylene diamine, followed by the quaternization of the tertiary amino group formed with the spacer of the ester group formed in the second step. The chemical configuration of the surfactants was established by FT-IR, 1HNMR, 13CNMR and Mass spectroscopies. The inhibition performance of three surfactants was studied by weight loss and electrochemical measurements. The results show that CGSES12, CGSES14 and CGSES16 behave as effective inhibitors and surface agents. The maximum efficiency was higher than 94% at 2.5 mM, and the inhibition order was CGSES16 > CGSES14 > CGSES12. This was due to the increment in hydrophobicity of the gemini surfactants. Their adsorption on a mild steel surface followed the Langmuir isotherm. CGSES12, CGSES14 and CGSES16 can be considered mixed-type inhibitors. The presence of CGSES12, CGSES14 and CGSES16 increased charge transfer resistance and decreased the corrosion rate. The adsorption focused on heteroatoms and the surface properties of cationic gemini surfactants.

Environmental Protection Performance of Anti-Collapse Agents with Different Hydrophobic Chain Lengths

2020 ◽  
Vol 56 (3) ◽  
pp. 363-372
Author(s):  
Yuan-Zhi Qu ◽  
Kai-Ping Tian ◽  
Ming-Yi Deng ◽  
Ren Wang ◽  
Jun Pu ◽  
...  
Keyword(s):  
Environmental Protection ◽  
Hydrophobic Chain ◽  
Chain Lengths

Effect of Hydrophilic- and Hydrophobic-Chain Lengths on the Phase Behavior of A−B-type Silicone Surfactants in Water

2001 ◽  
Vol 105 (23) ◽  
pp. 5419-5426 ◽  
Author(s):  
Hironobu Kunieda ◽  
Md. Hemayet Uddin ◽  
Makiko Horii ◽  
Haruhiko Furukawa ◽  
Asao Harashima
Keyword(s):  
Phase Behavior ◽  
Silicone Surfactants ◽  
Hydrophobic Chain ◽  
Chain Lengths

Phase Transitions of a Two-Dimensional Periodic Hydrophilic Hydrophobic Chain

1998 ◽  
Vol 09 (08) ◽  
pp. 1459-1468 ◽  
Author(s):  
Enzo Orlandini ◽  
Thomas Garel
Keyword(s):  
Phase Separation ◽  
Ground State ◽  
Square Lattice ◽  
Hydrophobic Core ◽  
Periodic Distribution ◽  
Hydrophobic Polymer ◽  
Markov Chain Method ◽  
Hydrophobic Chain ◽  
A Chain ◽  
Chain Lengths

We study a single self-avoiding hydrophilic hydrophobic polymer chain, through Monte Carlo lattice simulations. The affinity of monomer i for water is characterized by a (scalar) charge λi, and the monomer-water interaction is short-ranged. Assuming incompressibility yields an effective short ranged interaction between monomer pairs (i,j), proportional to (λi + λj). In this article, we take λi=+1 (resp. (λi=-1)) for hydrophilic (resp. hydrophobic) monomers and consider a chain with (i) an equal number of hydrophilic and -phobic monomers (ii) a periodic distribution of the λi along the chain, with periodicity 2p. This model may be of interest in various situations (protein folding, polysoaps, …) The simulations are done on the square lattice (d=2), for various chain lengths N. There is a critical value (pc(N)~0.07N) of the periodicity, which distinguishes between different low temperature structures. For p>pc, the ground state corresponds to a macroscopic phase separation between a dense hydrophobic core and hydrophilic loops. For p<pc (but not too small), one gets a microscopic (finite scale) phase separation, and the ground state corresponds to a chain or network of hydrophobic droplets, coated by hydrophilic monomers. These different cases will be explored through a Multiple Markov chain method. The results for the d=3 case (where pc(N)~N1/3) are similar.

Solubilization of Itraconazole by Surfactants and Phospholipid-Surfactant Mixtures: Interplay of Amphiphile Structure, pH and Electrostatic Interactions

2020 ◽  
Author(s):  
Zahari Vinarov ◽  
Gabriela Gancheva ◽  
Nikola Burdzhiev ◽  
Slavka S. Tcholakova
Keyword(s):  
Nmr Spectroscopy ◽  
Electrostatic Interactions ◽  
Triazole Ring ◽  
Water Soluble ◽  
Single Chain ◽  
Surfactant Mixtures ◽  
Solubilization Capacity ◽  
Water Soluble Drugs ◽  
Hydrophobic Chain ◽  
Brick Dust

Although surfactants are frequently used in enabling formulations of poorly water-soluble drugs, the link between their structure and drug solubilization capacity is still unclear. We studied the solubilization of the “brick-dust” molecule itraconazole by 16 surfactants and 3 phospholipid:surfactant mixtures. NMR spectroscopy was used to study in more details the drug-surfactant interactions. Very high solubility of itraconazole (up to 3.6 g/L) was measured in anionic surfactant micelles at pH = 3, due to electrostatic attraction between the oppositely charged (at this pH) drug and surfactant molecules. <sup>1</sup>H NMR spectroscopy showed that itraconazole is ionized at two sites (2+ charge) at these conditions: in the phenoxy-linked piperazine nitrogen and in the dioxolane-linked triazole ring. The increase of amphiphile hydrophobic chain length had a markedly different effect, depending on the amphiphile type: the solubilization capacity of single-chain surfactants increased, whereas a decrease was observed for double-chained surfactants (phosphatidylglycerols). The excellent correlation between the chain melting temperatures of phosphatidylglycerols and itraconazole solubilization illustrated the importance of hydrophobic chain mobility. This study provides rules for selection of itraconazole solubilizers among classical single-chain surfactants and phospholipids. The basic physics underpinning the described effects suggests that these rules should be transferrable to other “brick-dust” molecules.

A Monte Carlo Study of Flexible Polymer Chain Conformations in Restricted Volumes. I. A Model for Insoluble Blocks Conformations in Swollen Cores of Multimolecular Spherical Block Copolymer Micelles

1993 ◽  
Vol 58 (10) ◽  
pp. 2290-2304 ◽  
Author(s):  
Zuzana Limpouchová ◽  
Karel Procházka
Keyword(s):  
Monte Carlo ◽  
Block Copolymer ◽  
Monte Carlo Study ◽  
Volume Effect ◽  
Micellar Systems ◽  
Flexible Polymer ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Chain Conformations ◽  
Chain Lengths

Monte Carlo simulations of chain conformations in a restricted spherical volume at relatively high densities of segments were performed for various numbers of chains, N, and chain lengths (number of segments), L, on a tetrahedral lattice. All chains are randomly end-tethered to the surface of the sphere. A relatively uniform surface density of the tethered ends is guaranteed in our simulations. A simultaneous self-avoiding walk of all chains creates starting conformations for a subsequent equilibration. A modified algorithm similar to that of Siepmann and Frenkel is used for the equilibration of the chain conformations. In this paper, only a geometrical excluded volume effect of segments is considered. Various structural and conformational characteristics, e.g. segment densities gS(r), free end densities gF(r) as functions of the position in the sphere (a distance from the center), distributions of the tethered-to-free end distances, ρTF(rTF), etc. are calculated and their physical meaning is discussed. The model is suitable for studies of chain conformations is swollen cores of multimolecular block copolymer micelles and for interpretation of non-radiative excitation energy migration in polymeric micellar systems.

Rotationsbarriere der Endgruppen bei Poly- methinoxonolen verschiedener Kettenlänge / Rotation Barrier of the End Groups of Polymethine Oxonols with Different Chain Lengths

1976 ◽  
Vol 31 (8) ◽  
pp. 1017-1018 ◽  
Author(s):  
H. Oehling ◽  
F. Baer
Keyword(s):  
Nmr Spectra ◽  
Rotation Barrier ◽  
Free Enthalpy ◽  
Temperature Dependent ◽  
Restricted Rotation ◽  
H Nmr ◽  
Enthalpy Of Activation ◽  
End Groups ◽  
Electron Contribution ◽  
Chain Lengths

Abstract Polymethine oxonols show temperature dependent 1H-NMR-spectra because of restricted rotation of the end groups. The dependence of the value of the corresponding free enthalpy of activation AGt on the length of the poly-methine chain can be explained by the change of the π-electron contribution to ⊿G≠.

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