Organic Monolayers from 1-Alkynes Covalently Attached to Chromium Nitride: Alkyl and Fluoroalkyl Termination

Abstract

Strategies to modify chromium nitride (CrN) surfaces are important because of the increasing applications of these materials in various areas such as hybrid electronics, medical implants, diffusion barrier layers, corrosion inhibition, and wettability control. The present work presents the first surface immobilization of alkyl and perfluoro-alkyl (from C6 to C18) chains onto CrN substrates using appropriately functionalized 1-alkynes, yielding covalently bound, high-density organic monolayers with excellent hydrophobic properties and a high degree of short-range order. The obtained monolayers were characterized in detail by water contact angle, X-ray photoelectron spectroscopy (XPS), ellipsometry, and infrared reflection absorption spectroscopy (IRRAS).

Covalent Surface Modification of Oxide Surfaces

“…Also for this material the attachment of unsaturated hydrocarbons offers a versatile approach using non‐corrosive chemicals, as indicated in Figure 41 50. 146…”

“… Schematic representation of the formation of alkyne and alkene‐derived organic monolayers on a plasma‐activated, hydroxy‐terminated CrN surface 146…”

“…With increasing alkyl chain lengths, these films become increasingly well‐ordered and less tilted, as clear from a detailed IR analysis (Figure 42). 146…”

“…c) Overview: peak positions for 1‐hexyne to 1‐octadecyne monolayers: symmetric methylene stretch (ν a CH 2 , half‐filled squares), anti‐symmetric methylene stretch (ν a CH 2 , half‐filled circles), and asymmetric methyl stretch (ν a CH 3 , half‐filled triangles). d) Tilt angle with respect to the surface normal for varying molecular lengths 146…”

“…Binding mode of 2HHDA onto the oxidized CrN surface, resulting from the oxidative adsorption of the terminal alkyne functionality. c,d) XPS C1s narrow scan of 1‐hexadecyne and 2‐hydroxyhexadecanoic acid monolayers on plasma‐activated CrN surfaces 146…”