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2001 (1)
2000 (3)
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1Author    BoźennaR. Óźycka-Roszak, Romuald Żyłka, Janusz SarapukRequires cookie*
 Title    Hydration of Alkylammonium Salt Micelles -Influence of Bromide and Chloride Counterions  
 Abstract    Fax: (+48)-71 -2 0 5 -1 7 2 . E-mail: BO RO @ozi.ar.w roc.pl The micellization process of dodecyltrimethylammonium chloride (D TA C) and bromide (D T A B) was studied. N uclear magnetic resonance method was used. The 'H N M R and 13C N M R spectra were taken at higher and lower concentrations than the critical micelle concentrations (CM C) of the compounds studied. Chemical shifts were analysed. The studies perform ed were prompted by earlier calorim etric measurements which showed that there were significant qualitative and quantitative differences in the micellization process of the compounds studied. Namely, D T A B micelle dissociation was found to be an endothermic process while that of DTA C was exothermic. The differences found must be the result of differentiated influence of bromide and chloride counterions on the micellization process, including the phenomenon of micelle hydration. The objective of the work was to check whether cationic surfactant counterions can influence the micelle hydration process. Indeed, D TA B and D TAC, as monomers, exhibit similar hydrophobic hydration, but D TA B micelles are m ore hydrated than D TA C ones. It seems that the differences found in micellization of both salts studied may be attributed to different physicochemical properties of bromide and chloride ions, such as their mobilities and radii of their hydrated forms. M oreover, the effect of anions on the water structure must be taken into account. It is important whether the anions can be classified as water ordering kosmotropes, that hold the first hydration shell tightly, or water disordering chaotropes, that hold water molecules in that shell loosely. 
  Reference    Z. Naturforsch. 55c, 413 (2000); received January 10/March 6 2000 
  Published    2000 
  Keywords    Micelle Hydration, Calorimetry, Counterions 
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 TEI-XML for    default:Reihe_C/55/ZNC-2000-55c-0413.pdf 
 Identifier    ZNC-2000-55c-0413 
 Volume    55 
2Author    BożennaR. Óżycka-Roszak, Hanna PruchnikRequires cookie*
 Title    Influence of Dodecyltrimethylammonium Halides on Thermotropic Phase Behaviour of Phosphatidylcholine/Cholesterol Bilayers  
 Abstract    Effects of dodecyltrimethylammonium chloride (DTAC), dodecyltrimethylammonium bro­ mide (DTAB) and dodecyltrimethylammonium iodide (DTAI) on thermotropic phase behav­ iour of phosphatidylcholine bilayers containing cholesterol as well as on 'H N M R spectra were studied. Two series of experiments were performed. In the first one the surfactants were added to the water phase while in the other directly to the lipid phase (a mixed film from cholesterol, surfactant and phosphatidylcholine was formed). The effects of particular surfactants on the main phase transition temperature, Tm, were more pronounced when added to the lipid phase (2 nd method) than to the water phase (1 st method); the opposite happened when cholesterol was absent (Rözycka-Roszak and Pruchnik 2000, Z. Naturforsch. 55c, 240-244). Furthermore, in the case of the first method the transitions were asymmetrical while in the second method nearly symmetrical. It is suggested that surfactant poor and surfactant rich domains are formed when surfactants are added to the water phase. 
  Reference    Z. Naturforsch. 55c, 753—757 (2000); received March 27/May 11 2000 
  Published    2000 
  Keywords    Counterions, Phosphatidylcholine Bilayers, Cholesterol 
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 TEI-XML for    default:Reihe_C/55/ZNC-2000-55c-0753.pdf 
 Identifier    ZNC-2000-55c-0753 
 Volume    55 
3Author    BożennaR. Óżycka-Roszak, RomualdŻ. Yłka, TeresaK. Ral, A. Driana PrzyczynaRequires cookie*
 Title    Counterion Effects on Interaction of Amphiphilic Quaternary Ammonium Salts with Model Membranes  
 Abstract    The micellization as well as the interaction with model membranes of dodecyltrimethylam-monium halides (D T A X) and N-dodecyl-N,N-dim ethyl-N-benzylamm onium halides (D B eA X) were studied at 298K and 313K by means o f titration calorimetry. The calorimetric curves reflect both the counterion and benzyl group effects on the interaction o f the surfac­ tants studied with the lipid bilayer. Bromide as counterion enhanced the interactions more than chloride of both D TA X and D B eA X compounds with model membranes. Further, we studied the influence o f D TA X and D B eA X on calcium ion desorption from the liposom e membrane using a radioactive tracer method. D B eA X proved more efficient in desorption o f calcium than D TA X. Iodides of these compounds enhanced this process more than bromides and chlorides. 
  Reference    Z. Naturforsch. 56c, 407 (2001); received D ecem ber 4 2000/January 24 2001 
  Published    2001 
  Keywords    Counterions, M odel Membranes, Micellization 
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 TEI-XML for    default:Reihe_C/56/ZNC-2001-56c-0407.pdf 
 Identifier    ZNC-2001-56c-0407 
 Volume    56 
4Author    Janusz Sarapuk3, Halina Kleszczyriska3, JuliuszJoanna Pernakb, Bozenna Kalewskab, Rözycka-Roszak3Requires cookie*
 Title    Influence of Counterions on the Interaction of Pyridinium Salts with Model Membranes  
 Abstract    The interaction of pyridinium salts (PS) with red blood cells and planar lipid membranes was studied. The aim of the work was to find whether certain cationic surfactant counterion influence its possible biological activity. The counterions studied were C L , Br", I-, C 104~, BF4~ and N 0 3_. The model membranes used were erythrocyte and planar lipid membranes (BLM). At high concentration the salts caused 100% erythrocyte hemolysis (C 10o) or broke BLMs (CC). Both parameters describe mechanical properties of model membranes. It was found that the efficiency of the surfactant to destabilize model membranes depended to som e degree on its counterion. In both, erythrocyte and BLM experiments, the highest efficiency was observed for Br_, the lowest for N 0 3_. The influence o f all other anions on surfactant efficiency changed between these two extremities; that of chloride and perchlorate ions was similar. Some differences were found in the case o f BF4~ ion. Its influence on hemolytic possibilities of PS was significant while BLM destruction required relatively high concentration of this anion. Apparently, the influence of various anions on the destructive action of PS on the model membrane used may be attributed to different mobilities and radii o f hydrated ions and hence, to different possibilities o f particular anions to modify the surface potential of model membranes. This can lead to a differentiated interaction o f PS with m odi­ fied bilayers. Moreover, the effect of anions on the water structure must be taken into ac­ count. It is important whether the anions can be classified as water ordering kosm otropes that hold the first hydration shell tightly or water disordering chaotropes that hold water m olecules in that shell loosely. 
  Reference    Z. Naturforsch. 54c, 952 (1999); received April 6/May 20 1999 
  Published    1999 
  Keywords    M odel Membranes, Hemolysis, Stability, Cationic Surfactants, Counterions 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0952.pdf 
 Identifier    ZNC-1999-54c-0952 
 Volume    54 
5Author    Bożenna Różycka-Roszak, Hanna PruchnikRequires cookie*
 Title    Effect of Counterions on the Influence of Dodecyltrimethylammonium Halides on Thermotropic Phase Behaviour of Phosphatidylcholine Bilayers  
 Abstract    Effects of dodecyltrimethylammonium chloride (DTAC), dodecyltrimethylammonium bro­ mide (D T A B) and dodecyltrimethylammonium iodide (D T A I) on thermotropic phase behav­ iour of phosphatidylcholine bilayers as well as on !H NM R spectra were studied. In order to enhance the effect of counterions on water structure two series of experiments were per­ formed. In the first one the surfactants were added to the water phase and in the other one directly to lipid phase (a mixed film was formed). The effects o f particular surfactants on the main phase-transition temperature were more pronounced when they were added to the water phase (1st method) instead of the lipid phase (2nd method). Furthermore, in the case of the first method the transitions were found asymmetrical while in the second method nearly symmetrical. It is suggested that surfactant-poor and surfactant-rich domains are formed when surfactants are added to the water phase. 
  Reference    Z. Naturforsch. 55c, 240 (2000); received Novem ber 5/D ecem ber 15 1999 
  Published    2000 
  Keywords    Counterions, Dodecyltrimethylammonium Halides, Phase Behaviour, Phosphatidylcholine Bilayers 
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 TEI-XML for    default:Reihe_C/55/ZNC-2000-55c-0240.pdf 
 Identifier    ZNC-2000-55c-0240 
 Volume    55