# Surface-Active Amidequats with an Alkoxymethyl Substituent: Synthesis, Analysis, and Preliminary Evaluation as Potential Emulsifiers and Substitutes for Conventional Surfactants

## TL;DR

This paper introduces new eco-friendly amidequat compounds with improved surface activity, showing promise as emulsifiers and surfactant alternatives in cleaning and cosmetic products.

## Contribution

The study presents novel surface-active amidequats with alkoxymethyl substituents and evaluates their potential as emulsifiers and surfactant substitutes.

## Key findings

- Amidequats with 12 carbon atoms in the alkyl chain show the highest surface and foam-forming activity.
- Amidequats outperform sodium caprylate in micellization properties.
- Oil-in-water and water-in-oil emulsions using amidequats were successfully prepared and analyzed.

## Abstract

Amidequats have attracted considerable attention in research;
however,
their surface activity remains largely unknown, and their potential
as emulsifiers is still unexplored. In this work, series of novel
surface-active amidequats based on ecofriendly caprylic acid were
synthesized and their micellization behavior in water was explored
systematically. The surface tension, wettability, foamability and
stability, and measurements of melting and crystallization temperatures
were employed to characterize the compounds. The functionalization
of amidequats containing an alkoxymethyl substituent significantly
enhances micellization properties compared to the structurally analogous
anionic surfactant, sodium caprylate. Moreover, for optimized molecule
geometries, electrical dipole moments were determined and correlated
with surface activity. Experimental and theoretical studies indicate
that amidequats with 12 carbon atoms in the alkyl chain exhibit the
highest surface and foam-forming activity, making them promising emulsifiers.
Due to this fact, oil-in-water (o/w) or water-in-oil (w/o) emulsions
using the mentioned amidequat were prepared, and their rheological
analysis, ζ potential, topography analysis, and particle size
were studied. A detailed investigation of the surface properties of
amidequats was undertaken to assess their potential application in
the cleaning agent and cosmetic industries.