Fluoroalkylsilanes with Embedded Functional Groups as Building Blocks for Environmentally Safer Self-Assembled Monolayers

Barbara Ballarin; Davide Barreca; Maria Cristina Cassani; Giorgio Carraro; Chiara Maccato; Adriana Mignani; Dario Lazzari; Maurizio Bertola

doi:10.1021/acs.langmuir.5b01416

Fluoroalkylsilanes with Embedded Functional Groups as Building Blocks for Environmentally Safer Self-Assembled Monolayers

Langmuir. 2015 Jun 30;31(25):6988-94. doi: 10.1021/acs.langmuir.5b01416. Epub 2015 Jun 19.

Authors

Barbara Ballarin¹, Davide Barreca², Maria Cristina Cassani¹, Giorgio Carraro³, Chiara Maccato³, Adriana Mignani⁴, Dario Lazzari⁵, Maurizio Bertola⁵

Affiliations

¹ †Department of Industrial Chemistry "Toso Montanari", UdR INSTM of Bologna and Center for Industrial Research-Advanced Applications in Mechanical Engineering and Materials Technology (CIRI-MAM), Alma Mater Studiorum, University of Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy.
² ‡CNR-IENI and INSTM, Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy.
³ §Department of Chemical Sciences, University of Padova and INSTM, Via Marzolo 1, I-35131 Padova, Italy.
⁴ ∥Center for Industrial Research-Advanced Applications in Mechanical Engineering and Materials Technology (CIRI-MAM), University of Bologna, Viale del Risorgimento 2, I-40136 Bologna, Italy.
⁵ ⊥Miteni S.p.A., Località Colombara 91, I-36070 Trissino, Vicenza, Italy.

PMID: 26068136
DOI: 10.1021/acs.langmuir.5b01416

Abstract

The fabrication of silane-based fluorinated self-assembled monolayers (FSAMs) on indium tin oxide (ITO, a transparent electrode) was carried out making use of the following fluoroalkylsilanes (FAS): 2,2,3,3,4,4,5,5,6,6,6-undecafluoro-N-[3-(trimethoxysilyl)propyl]hexanamide (1; R(F) = C5F11) and 1,1,2,2,3,3,4,4,4-nonafluoro-N-[3-(trimethoxysilyl)propyl]butane-1-sulfonamide (2; R(F) = C4F9), containing an embedded amide and a sulfonamide group, respectively, between the short perfluoroalkyl chain (R(F) with C < 6) and the syloxanic moiety. The obtained FSAM-modified/ITO systems were characterized by X-ray photoelectron spectroscopy (XPS), contact angle (CA), surface energy measurements, and electrochemical impedance spectroscopy (EIS) and compared to ITO modified with a 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyltriethoxysilane (3; R(F) = C6F13), with the perfluoroalkyl group linked to the syloxanic moiety through a simple hydrocarbon chain. The results obtained show that the presence of the -NHCO- and -NHSO2- groups have a different mode of action and, with the former, despite the short perfluoroalkyl chain, the ITO-1 system presents a CA (Θ(water )= 113.5°) and surface energy (γl = 14.0 mJ m(-2)) typical of amphiphobic materials. These properties can be exploited in a variety of applications, such as self-cleaning, anti-fouling, and anti-fingerprint coatings, and in advanced microelectronic components.