A comparative study on surface and foam properties of natural and synthetic surfactants and characterization of natural surfactants

Abstract

Surfactants or surface active agents are molecules exhibiting various interfacial newlineactivities. Amphiphilicity of surfactants is responsible for surface tension newlinereduction, exhibiting a wide range of pharmaceutical and industrial applications. newlineFoaming is an important property of surfactants. Foam is a system of newlinegas phase distributed in a liquid phase. They have varied applications in the newlineeveryday world. Synthetic surfactants are used extensively today. After use, newlinethey enter the aquatic environment and cause damage. Keeping in view the newlineenvironmental burden, it is desirable to substitute synthetic surfactants with newlinenaturally obtained molecules as renewable and bio-compatible alternatives. newlineIn search of such alternatives, I have investigated a few plant based natural newlinesurfactants.This thesis presents detailed investigations of surface and foam properties newlineof natural surfactants extracted from Sapindus mukorossi, Albizia procera, newlineZephyranthes carinata, Acacia concinna and Juglans regia. Some synthetic newlinesurfactants have been studied as a reference. In addition, I have also performed newlinepreliminary characterization of the natural surfactants using Thin newlineLayer Chromatography (TLC), Column Chromatography (CC), High Performance newlineLiquid Chromatography (HPLC), UV-Visible Spectroscopy (UVVis), newlineFourier Transform Infrared Spectroscopy(FTIR) and Gas Chromatography newlineMass Spectrometry (GC-MS). Also, the thesis discusses one shot newlinetwo dimensional drainage in foams using natural surfactant systems. While newlineSapindus mukorossi and Acacia concinna have been studied earlier, this thesis gives the first ever reports on surfactant activities of Albizia procera, newlineZephyranthes carinata and Juglans regia. newlineThe surface tension studies reveal that good surface tension reduction newlinewas observed for all the natural surfactants with a low critical micelle concentration newline(CMC). The natural surfactants are acid balanced and exhibited newlinegood wetting ability. Juglans regia is an exception. On addition of salt, the newlinefoaming increases and then decreases when surfactant concent