Amphiphilic properties of dodecylammonium chloride/sodium 4-(1-pentylheptyl) benzenesulfonate aqueous mixtures and study of the catanionic complex

Surfactants are often used in supramolecular chemistry, due to their ability to self-organize. Surfactant molecules aggregate spontaneously and reversibly to adopt a defined intermolecular arrangement. In this work, general phase behavior, adsorption and association in aqueous mixtures of dodecylammonium chloride, DACl and sodium 4-(1-pentylheptyl)benzenesulfonate, NaDBS, were studied by a combination of techniques including surface tension and conductivity measurements, light scattering and optical microscopy. The strong synergistic properties of the system were brought out with the Regular Solution Theory.Various colloidal objects are observed in wide range of composition: conventional small vesicles, large giant multilamellar or multivesicular vesicles. An excess of NaDBS provides extremely large tubular and elongated multilamellar vesicles. The new catanionic 1:1 complex, dodecylammonium 4-(1-pentylheptyl) benzenesulfonate, formed in the equimolar conditions is a result of intramolecular charge neutralization. The thermal properties of this solid compound were examined by thermal polarizing microscopy, differential scanning calorimetry, and X-ray diffraction. The most probable ion-pair amphiphilic cluster of crystal smectic phase, at room temperature, consists of ionic groups formed in ordered layers with dodecyl chains packed into somewhat disordered layers, tilted to the layer plane

Morphological characterization of the catanionic amphiphiles

Suvremeni život vrlo je kompleksan. Smatra se daje spontana transformacija nežive tvari u žive subjekte rezultat kontinuiranih evolucijskih predbioloških procesa, povezanih s porastom molekulske i supramolekulske organizacije. Područje supramolekulske kemije, u koje pripada i samoasociranje amfifilnih molekula, može pridonijeti razvoju istraživanja i različitim primjenama na području medicine, biologije i kemije, kao i znanstvenom razumijevanju života, zdravlja, dijagnostike i terapije. Kruti katanionski amfifili nastaju međudjelovanjem amfifila ili sličnih amfifilnih biomolekulskih tvari, suprotnih elektrostatskih naboja u vodenim otopinama. Uređenje i preferirani oblik katanionskih supramolekulskih agregata posljedica su prvenstveno elektrostatskih međudjelovanja, te orijentacijskih hidrofilno-hidrofobnih svojstava dotične kombinacije molekula. Analiza morfoloških karakteristika niza različitih katanionskih liotropa i termotropa omogućuje povezivanje njihove kemijske strukture s mezostrukturom i odgovarajućim fizikalno-kemijskim svojstvima.Contemporary life is very complex. The spontaneous transformation of non-living matter to living entities is considered to be a result of a continuous evolutional and prebiological process during which the molecular and supramolecular complexity increased. The field of supramolecular chemistry, to which the self-association of amphiphilic molecules belongs, may contribute to the development of research and different applications in the fields of biology, medicine and chemistry, and to the scientific understanding of life, health, diagnostic and therapy. Solid catanionic amphiphils can be synthesized by interaction between amphiphils or similar amphiphilic biomolecular compounds of the opposite electrostatic charge in aqueous solutions. Arrangement and preferred shape of catanionic supramolecular aggregates are consequence of primarily electrostatic interactions and preferred hydrophilic and hydrophobic orientation of the abovementioned combination of molecules. Analysis of the morphological characteristics of many different catanionic lyotropic and thermotropic liquid crystals allows association of their chemical structures with related mesostructures and corresponding physicochemical properties

Study of surfactants role in remediation of hydrosphere and synthesis of new materials

U cilju sniženja koncentracija najzastupljenijih površinski aktivnih tvari u hidrosferi, istraživana su fizikalno-kemijska svojstva otopina pojedinačnih amfifila, te njihovih kationskih i anionskih smjesa, u raznim koncentracijskim i temperaturnim uvjetima, te uz dodatak anorganskoga ili organskoga elektrolita. Određivane su granice taloženja i konstruirani precipitacijski dijagrami. Na temelju mjerenja površinske napetosti i električne provodnosti određena su svojstva adsorpcije na granici faza otopina-zrak, te mehanizmi amoorganizacije amfifila u vodenim otopinama. Objašnjen je princip nastajanja katanionskih amfifila, registrirana su njihova termotropna svojstva, te provedena molekulska simulacija njihovih struktura. Takva istraživanja postaju sve značajniji aspekt koloidne kemije, a ključni su dio znanosti o okolišu u cilju očuvanja ljudskoga zdravlja, čime pridonose liječnicima i medicinarima u biomedicinskim istraživanjima, a važna su i za strategiju razvoja kompleksnih novih nanostrukturiranih materijala.In order to decrease the concentrations of the most representative surfactants in hydrosphere, physico-chemical properties of individual surfactants and their cationic and anionic mixtures were studied at different concentration and temperature conditions, and with the addition of inorganic or organic electrolyte. The sedimentation borders and precipitation diagrams were constructed. The adsorption properties at the solution-air interface, and the mechanisms of surfactant self-organization in aqueous solutions were determined by measuring the surface tension and electrical conductance. The principle of catanionic amphiphiles formation is explained, their thermotropic properties are registered, and the molecular simulation of structure is conducted. Such examinations become an increasingly important aspect of environmental science for the protection of human health, with the great contribution to doctors and medical staff in biomedical research, and are also important for the development of strategies for synthesis of new complex nano-structured materials

Importance of investigation of bile salts and their derivatives as building blocks of supramolecular hosts for the purpose of treatment

Prikazan je niz fizikalno-kemijskih metoda i tehnika korištenih u ispitivanju modelnih žučnih sustava. Ispitano je međudjelovanje anionske, biološke površinski aktivne tvari, natrijevoga kolata i sintetskih jednolančanih i dvolančanih površinski aktivnih tvari, te natrijeva kolata i metalnih iona rastućega naboja. Sustavi omogućuju novi pogled na kompleksne postupke taloženja, vezikulacije i geliranja, te bolje razumijevanje procesa koji se odvijaju u živom organizmu. Utvrđena je zavisnost svojstava molekula žučnih soli i njihovih derivata o molekulskim međudjelovanjima, molekulskom pakiranju i svojstvima kristalnoga taloga, tako da se mogu koristiti kao supramolekulski receptori za različite vrste gostujućih molekula i iona, te u dizajnu budućih materijala. Takva istraživanja nalaze svoj značaj u fiziologiji (u dijagnozi ili razvoju novih farmakoloških pripravaka) ili patofiziologiji (u sprječavanju štetnih reakcija, kao npr. taloženja), ukazujući na usku povezanost medicine s biotehnologijom, organskom, makromolekulskom, anorganskom i fizikalnom kemijom.This article reports a variety of physico-chemical methods and techniques that have been used in the research of native, model bile systems. Interactions of the anionic biological surfactant, odium cholate and synthetic single- and double- chained surfactants, as well as sodium cholate and metal ions with increasing charges, were examined. These systems provide new insight into the complex processes of precipitation, vesiculation and gelation, and better understanding of those that take place in the living organism. The dependence of molecules of bile salts and their analogues on molecular interactions, molecular packing and properties of crystalline materials is established, so they can be utilized as supramolecular receptors for various types of guest molecules and ions, and for the design of novel materials. Such researches find their physiological (in diagnosis or developing new pharmacological applications) or pathophysiological relevance (in preventing harmful reactions, such as precipitation), and show close relationship between medicine and biotechnology, organic, macromolecular, inorganic and physical chemistry