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Updated: May 24, 2025
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Published on: October 29, 2013
Molecular Behavior of Amide Wax Molecules on Carboxylic Acid-Functionalized Polyethylene Surfaces
Jianing Gan1, Gladwin Labrague1, Hanze Ying2
1Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48103, United States.
Abstract:
Self-assembled monolayers (SAMs) are highly ordered thin coatings that provide a variety of excellent properties to the material surface. They bestow unique properties to the material such as hydrophobicity, lubrication, and barrier performance but are challenging to investigate due to their low concentrations. In this study, we investigate the SAM formation of amide wax components that segregate from the carboxylic acid-functionalized polyethylene coating bulk and self-assemble at the surface. We applied sum frequency generation (SFG) vibrational spectroscopy to study the SAM formations and the resulting structures of segregated surface waxes as a function of the wax/polymer ratio, polymer matrix formulation, and wax molecule types. It was found that the type of wax molecules, the wax concentration, and the composition of the polymer matrix strongly influence the quality of the formed SAM. Increasing the heat treatment temperature had positive effects on the waxes that were weakly trapped by the bulk matrices but did not impact the waxes interacting strongly with the polymer matrix.
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01:28Amides to Carboxylic Acids: Hydrolysis
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
01:19Physical Properties of Carboxylic Acid Derivatives
Among the carboxylic acid derivatives, the boiling points of acid chlorides and esters are very similar and are the lowest in the series. Acid anhydrides have slightly higher boiling...
01:19Amines to Amides: Acylation of Amines
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01:11Nomenclature of Carboxylic Acid Derivatives: Amides and Nitriles
The IUPAC and common names of amides are derived from the parent carboxylic acid, by replacing the suffix “oic acid” and “ic acid,” respectively, with “amide.” In the following example, the IUPAC name ethanamide is derived from ethanoic acid, and the common name, acetamide, is obtained from acetic acid.
01:29Preparation of Amides
The DCC-promoted synthesis of amides begins with the protonation of DCC by carboxylic acid. The protonation makes it a better acceptor. Next, the addition of carboxylate to the protonated carbodiimide gives a reactive acylating agent.
Subsequently, the amine acts as a nucleophile that attacks the acylating agent to form a tetrahedral intermediate. In the...
01:28Structures of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
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