Polymeric Self-Assembled Monolayers. 4. Synthesis, Characterization, andStability of omega-Functionalized, Self-Assembled Diacetylenic and Polydiacetylenic Monolayers

摘要

Here we discuss the preparation and characterization of photopolymerizable, self-assembled monolayers (SAMs) that consist of acid-, hydroxyl-, and methyl-terminated n-alkylthiois containing a diacetylene group (HS(CH 2)10C equivalent C(triple bonds)CC(triples bonds)C(CH2)10X; X=COOH, CH2OH, and CH3, respectively). The acid and hydroxyl surfaces are readily amenable to further synthetic elaboration, while the methyl-terminated SAM results in a clean, low-energy surface. As demonstrated by Fourier transform infrared external reflectance spectroscopy (FTIR-ERS), surface-enhanced Raman spectroscopy (SERS), ellipsometry, UV-vis spectroscopy, and electrochemical methods, all three materials self assemble onto Au surface to form ordered monolayers that can be photopolymerized with UV light. The polymerized SAMs are extremely durable compared to simple n-alkanethiol SAMs. For example, they are stable to electrochemical cycling, thermal excursions to 200 deg C, and exposure to hot base (1:1 mixture of ethanol and 1.0 M aqueous KOH at 100 deg C). All of these conditions completely strip n-alkanethiol SAMs from Au substrates. These high-performance materials are suitable for applications in lubrication, adhesion, corrosion inhibition, and chemical sensing.