Comparative Studies of Film-Forming Properties of partially Fluorinated Tetracosanes

• Autorzy: Broniatowski M. , Miňones J. , Sandez Macho I , Dynarowicz-Łątka P.
• Języki publikacji: EN

Abstrakty

EN

Contrary to simple n-alkanes of moderate molecular weight, which are not capable of Langmuir monolayer formation, partially fluorinated hydrocarbons of the general formula: F(CF2)m(CH2)nH (abbreviated as FmHn) were found to form monomolecular layers at the air/water interface. The aim of this study was to characterize several semifluorinated alkanes (SFA) containing 24 carbon atoms in total (tetracosanes) differing in the m/n ratio, as Langmuir monolayers at the free water surface. The following compounds have been investigated: F4H20, F6H18, F8H16, F10H14 and F12H12. Surface pressure (pi) and electric surface potential deltaV) isotherms were recorded in addition to quantitative Brewster angle microscopy results. The negative sign of deltaV evidenced for the orientation of all the semifluorinated tetracosanes investigated here, regardless the length of the hydrogenated segment, with their perfluorinated parts directed towards the air. As inferred from apparent dipole moment values and relative reflectivity results, tetracosanes with shorter perfluorinated fragment (F4H20 and F6H18) were found to take vertical orientation at the air/water interface, while those with longer perfluorinated moiety (F8H16, F10H14 and F12H12) remain tilted even in the vicinity of the film collapse. The observed differences may result from a different conformation of the perfluorinated chain, i.e. more fluorinated tetracosanes (F10H14 and F12H12) have their perfluorinated parts sufficiently long to form a helix, while less fluorinated derivatives (F4H20 and F6H18) may possibly exist in all-trans configuration. In particular, the perfluorinated fragment in F8H16 is considered to have an intermediate character between these two structures.

Słowa kluczowe

EN

Langmuir monolayers; air/water interface; semifluorinated alkanes; surface potential; effective dipole moments; Brewster angle microscopy

• Wydawca: Polskie Towarzystwo Chemiczne
• Czasopismo: Polish Journal of Chemistry
• Rocznik: 2005
• Tom: Vol. 79 / nr 6
• Strony: 1047--1061
• Opis fizyczny: Bibliogr. 32 poz., rys.

Twórcy

autor

Broniatowski M.

• Jagiellonian University, Faculty of Chemistry, Ingardena 3, 30-060 Kraków, Poland

autor

Miňones J.

• University of Santiago de Compostela, Faculty of Pharmacy, Department of Physical Chemistry, 15-706 Santiago de Compostela, Spain

autor

Sandez Macho I

• University of Santiago de Compostela, Faculty of Pharmacy, Department of Physical Chemistry, 15-706 Santiago de Compostela, Spain

autor

Dynarowicz-Łątka P.

• Jagiellonian University, Faculty of Chemistry, Ingardena 3, 30-060 Kraków, Poland

Bibliografia

• 1.Brace N.O., J. Org. Chem., 27, 3033 (1962).
• 2.Rabolt J.F., Russell T.P. and Twieg R.J., Macromolecules, 17, 2786 (1984).
• 3.Hildebrandt J.H., J. Am. Chem. Soc., 72, 4348 (1950).
• 4.Turberg M.P. and Brady J.E., J. Am. Chem. Soc., 110, 7797 (1988).
• 5.Lo Nostro P., Adv. Colloid Interface Sci., 56, 245 (1995).
• 6.Binks B.P., Fletcher P.D., Sager W.F. and Thompson R.L., Langmuir, 11, 977 (1995).
• 7.Binks B.P., Fletcher P.D., Kotsev S.N. and Thompson R.L., Langmuir, 13, 6669 (1997).
• 8.Lo Nostro P. and Chen S.H., J. Phys. Chem., 97, 6535 (1993).
• 9.Binks B.P., Fletcher P.D., Sager W.F. and Thompson R.L., J. Mol Liquids, 72, 177 (1997).
• 10.Twieg R.J., Russell T.P., Siemens R. and Rabolt J.F., Macromolecules, 18, 1361 (1985).
• 11.Hopken J., Pugh C., Richtering W. and Moller M., Makromol. Chem., 189, 911 (1988).
• 12.Napoli M., Conte L. and Guerrato A., J. Fluorine Chem., 110, 47 (2001).
• 13.Gaines G.L. Jr., Langmuir, 7, 3054 (1991).
• 14.Huang Z., Acero A.A., Lei N., Rice S.A., Zhang Z. and Schlossman M.C., J. Chem. Soc., Faraday Trans., 94, 545 (1996).
• 15.El Abed A., Faure M.C., Hamdani M., Guittard F., Billard J. and Peretti P., Mol. Cryst. Liq. Cryst., 329, 283 (1999).
• 16.El Abed A., Pouzet E., Faure M.C., Sanicre M. and Abillon O., Phys. Rev. E, 62, R5895 (2000).
• 17.El Abed A., Faure M.C., Pouzet E. and Abillon O., Phys. Rev. E, 65, 0516031 (2002).
• 18.Maaloum M., Muller P. and Krafft M.P., Angew. Chem. Int. Ed., 41, 4331 (2002).
• 19.Krafft M.P., Giulieri F., Fontaine P. and Goldmann M., Langmuir, 17, 6577 (2001).
• 20.Azzam R.M.A. and Bashara N.M., Ellipsometry and Polarized Light, 1st ed., North Holland, Amsterdam 1992.
• 21.Davies J.T. and Rideal E.K., Interfacial Phenomena, 2nd Edition, Academic Press, New York, 1963, pp. 265 and 65.
• 22.Harkins W.D., The Physical Chemistry of Surface Films, Reinhold, New York, 1952, p. 107.
• 23.Reis T., Introduction a !a Chimie-Physique des Surfaces, Dunod, Paris, 1952, p. 111.
• 24.Leite V.B.P., Cavalli A. and Oliveira O.N., Jr., Phys. Rev E, 57, 6835 (1998).
• 25. Gaines G.L. Jr., Insoluble Monolayers at Liquid-Gas Interfaces, John Wiley & Sons Int. 1966.
• 26. Minkin V.L., Osipov O.A. and Zhdanov Y. A., Dipole Moments in Organic Chemistry, P WN, Warszawa 1970, p. 91, (in Polish).
• 27.Davies J.T. and Rideal EX., Can. J. Chem., 33, 947 (1955).
• 28. Hyper Chem Professional Release 5.1 ,A Molecular Visualization and Simulation Software Package. Hvpcrcube Inc., Gainesville, Florida, USA, 1998.
• 29.Saswart J J.P., J. Comp. Chem., 10, 221 (1989).
• 30.Bunn C.W. and Howells E.R., Nature, 174, 549 (1954).
• 31.C., Russell T.P., Depero L.E. and Twieg R.J., Mol. Cryst. Liq. Cryst., 168, 63 (1989).
• 32. Wang J. and Ober C.K., Liq. Cryst., 26, 637 (1999).