title: Boojum and stripe textures in long-range orientationally ordered monolayers on solid substrates.
abstract: Long-range organization of molecular tilt azimuth is a striking feature in monolayers at the air-water interface. We show that the boojum and stripe textures of pentadecanoic acid (PDA) with the continuous variations of molecular tilt azimuth formed at the air-water interface at temperatures lower than room temperature can be preserved after being transferred to glass substrates at low dipping speeds. The long-range tilt order in the transferred boojums and stripes is resolved by frictional force microscopy at room temperature, suggesting that the tilt order is "frozen" through the interaction of PDA molecules with the glass surface. The transferred stripe structure can be used as a unique alignment layer to induce a continuously azimuthal orientation of nematic liquid crystals.
authors.affiliation: Advanced Materials Processing and Analysis Center and Mechanical, Materials and Aerospace Engineering, University of Central Florida, Orlando, Florida 32826, United States.
authors.forename: Wenlang
authors.initials: W
authors.lastname: Liang
authors.forename: Tanmay
authors.initials: T
authors.lastname: Bera
authors.forename: Xuejun
authors.initials: X
authors.lastname: Zhang
authors.forename: Andre J
authors.initials: AJ
authors.lastname: Gesquiere
authors.forename: Jiyu
authors.initials: J
authors.lastname: Fang
mesh_terms: D000388:Air; D005227:Fatty Acids / Q000737:chemistry; D050866:Liquid Crystals / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D013499:Surface Properties; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D005227:Fatty Acids; D014867:Water; C117025:pentadecanoic acid