title: Surface and liquid-crystalline properties of FmHnFm triblock semifluorinated n-alkanes.
abstract: A series of triblock semifluorinated n-alkanes of the general formula: F(CF2)m(CH2)n(CF2)mF, (in short FmHnFm), where m=10, 12, and n=6, 8, and 12 have been synthesized and employed for liquid crystalline studies and Langmuir monolayer characterization. Differential scanning calorimetry (DSC) measurements together with texture observation with polarizing microscope (POM) revealed the presence of liquid crystalline smectic phases for all the investigated homologs. The behavior of the studied molecules spread at the free water surface has also been investigated. Our results show for the first time that these unusual film-forming materials, which are completely hydrophobic in nature and do not possess any polar group in their structure, are surface active and form insoluble (Langmuir) monolayers at the air/water interface. Due to the fact that these molecules are chemically inert and, similar to the semifluorinated diblocks, are not toxic, they may be destined for biomedical uses as gas carriers and contrast agents, as well as in drug delivery systems.
authors.affiliation: Jagiellonian University, Faculty of Chemistry, Ingardena 3, 30-060 Kraków, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Chachaj-Brekiesz
authors.affiliation: Jagiellonian University, Faculty of Chemistry, Ingardena 3, 30-060 Kraków, Poland.
authors.forename: Natalia
authors.initials: N
authors.lastname: Górska
authors.affiliation: The Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland.
authors.forename: Natalia
authors.initials: N
authors.lastname: Osiecka
authors.affiliation: Jagiellonian University, Faculty of Chemistry, Ingardena 3, 30-060 Kraków, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Makyła-Juzak
authors.affiliation: Jagiellonian University, Faculty of Chemistry, Ingardena 3, 30-060 Kraków, Poland. Electronic address: ucdynaro@cyf-kr.edu.pl.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Dynarowicz-Łątka
mesh_terms: D000473:Alkanes / Q000138:chemical synthesis / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D054879:Halogenation; D050866:Liquid Crystals / Q000737:chemistry*; D044367:Phase Transition; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D000473:Alkanes; D014867:Water
keywords: Langmuir monolayers; Liquid crystals; Thermal behavior; Triblock semifluorinated alkanes