Adsorption of Sodium Dodecyl Sulfate on Ge Substrate: The Effect of a Low-Polarity Solvent

Rommel B Viana,Albérico B F Da Silva,André S Pimentel

doi:10.3390/ijms13077980

Abstract

This paper describes the adsorption of sodium dodecyl sulfate (SDS) molecules in a low polar solvent on Ge substrate by using Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy and atomic force microscopy (AFM). The maximum SDS amount adsorbed is (5.0 ± 0.3) × 1014 molecules cm−2 in CHCl3, while with the use of CCl4 as subphase the ability of SDS adsorbed is 48% lower. AFM images show that depositions are highly disordered over the interface, and it was possible to establish that the size of the SDS deposition is around 30–40 nm over the Ge surface. A complete description of the infrared spectroscopic bands for the head and tail groups in the SDS molecule is also provided.

Highlights

Surfactant deposition on substrates has been widely studied due to its significance in both applied and fundamental processes [1]
This study describes the sodium dodecyl sulfate (SDS) deposition on Ge substrate by using Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy and atomic force microscopy (AFM)
The maximum amount deposited is (5.0 ± 0.3) × 1014 molecules·cm−2 in CHCl3, with the use of CCl4 as subphase, the SDS deposition is 48% lower than with CHCl3

Summary

Introduction

Surfactant deposition on substrates has been widely studied due to its significance in both applied and fundamental processes [1]. The determination of the packing, and ordering, and their relation to the properties of the surfactant aggregates is of fundamental importance [2,3]. These properties have been widely investigated and used to infer aggregation on substrates. The understanding of the structure and conformation of these aggregates has been limited due to a lack of suitable tools to determine the ordering and packing of the surfactants on substrates [4,5,6,7]. 2012, 13 investigate the interaction between surfactant and substrate are Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy and atomic force microscopy (AFM). The inability of infrared spectroscopists to assign some band features has been the main barrier to advance in studying the organization and conformation of few surfactants monolayers using FTIR-ATR [4,5,6,7,16]

Objectives

Results

Conclusion