title: Robust carboxylic acid-terminated organic thin films and nanoparticle protectants generated from bidentate alkanethiols.
abstract: A new carboxylic acid-terminated alkanethiol having bidentate character, 16-(3,5-bis(mercaptomethyl)phenoxy)hexadecanoic acid (BMPHA), was designed as an absorbate and protectant to form thermally stable carboxylic acid-terminated organic thin films on flat gold and nanoparticles, respectively. The structural features of the organic thin films derived from BMPHA were characterized by ellipsometry, X-ray photoelectron spectroscopy (XPS), and polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), and compared to those derived from mercaptohexadecanoic acid (MHA) and 16-(4-(mercaptomethyl)phenoxy)hexadecanoic acid (MMPHA). This study demonstrates that films derived from BMPHA are less densely packed than films derived from MHA and MMPHA. However, the results of solution-phase thermal desorption tests revealed that the carboxylic acid-terminated films generated from BMPHA exhibit an enhanced thermal stability compared to those generated from MHA and MMPHA. Furthermore, as a nanoparticle protectant, BMPHA can be used to stabilize large gold nanoparticles (~45 nm diameter) in solution, and BMPHA-protected gold nanoparticles exhibited a high thermal stability in solution thermolysis studies.
authors.affiliation: Department of Chemistry and the Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Houston, Texas 77204-5003, USA.
authors.forename: Han Ju
authors.initials: HJ
authors.lastname: Lee
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Jamison
authors.forename: Yuehua
authors.initials: Y
authors.lastname: Yuan
authors.forename: Chien-Hung
authors.initials: CH
authors.lastname: Li
authors.forename: Supachai
authors.initials: S
authors.lastname: Rittikulsittichai
authors.forename: Irene
authors.initials: I
authors.lastname: Rusakova
authors.forename: T Randall
authors.initials: TR
authors.lastname: Lee