title: Synthesis and characterization of polydiacetylene films and nanotubes.
abstract: We report here the synthesis and characterization of polydiacetylene (PDA) films and nanotubes using layer-by-layer (LBL) chemistry. 10,12-Docosadiyndioic acid (DCDA) monomer was self-assembled on flat surfaces and inside of nanoporous alumina templates. UV irradiation of DCDA provided polymerized-DCDA (PDCDA) films and nanotubes. We have used zirconium-carboxylate interlayer chemistry to synthesize PDCDA multilayers on flat surfaces and in nanoporous template. PDCDA multilayers were characterized using optical (UV-vis, fluorescence, ellipsometry, FTIR) spectroscopies, ionic current-voltage ( I- V) analysis, and scanning electron microscopy. Ellipsometry, FTIR, electronic absorption and emission spectroscopies showed a uniform DCDA deposition at each deposition cycle. Our optical spectroscopic analysis indicates that carboxylate-zirconium interlinking chemistry is robust. To explain the disorganization in the alkyl portion of PDCDA multilayer films, we propose carboxylate-zirconium interlinkages act as "locks" in between PDCDA layers which restrict the movement of alkyl portion in the films. Because of this locking, the induced-stresses in the polymer chains can not be efficiently relieved. Our ionic resistance data from I- V analysis correlate well with calculated resistance at smaller number of PDCDA layers but significantly deviated for thicker PDCDA nanotubes. These differences were attributed to ion-blocking because some of the PDCDA nanotubes were totally closed and the nonohmic and permselective ionic behaviors when the diameter of the pores approaches the double-layer thickness of the solution inside of the nanotubes.
authors.affiliation: Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois 62901, USA. pkohli@chem.siu.edu
authors.forename: Erastus
authors.initials: E
authors.lastname: Gatebe
authors.forename: Hayley
authors.initials: H
authors.lastname: Herron
authors.forename: Rashid
authors.initials: R
authors.lastname: Zakeri
authors.forename: Pradeep
authors.initials: P
authors.lastname: Ramiah Rajasekaran
authors.forename: Samir
authors.initials: S
authors.lastname: Aouadi
authors.forename: Punit
authors.initials: P
authors.lastname: Kohli
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry; D004867:Equipment Design; D007477:Ions; D008855:Microscopy, Electron, Scanning; D015233:Models, Statistical; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry*; D000078789:Polyacetylene Polymer; D011108:Polymers / Q000737:chemistry*; D053279:Polyynes / Q000737:chemistry*; D011791:Quartz; D013050:Spectrometry, Fluorescence / Q000379:methods; D013053:Spectrophotometry / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D015040:Zirconium / Q000737:chemistry
chemical_list: D002264:Carboxylic Acids; D007477:Ions; D000078789:Polyacetylene Polymer; D011108:Polymers; D011791:Quartz; D053279:Polyynes; C082361:polydiacetylene; D015040:Zirconium