Comparison of Cleaning Power Between Alcohol Ethoxylates or Methyl Ester Ethoxylates Having Different EO Chain Lengths and a Common Anionic Surfactant

Abstract

Cleaning power of different surfactants was investigated using a model detergent system consisting of a PET film and stearic acid. Surfactants used were alcohol ethoxylates (AE, C12) and methyl ester ethoxylates (MEE, C12) with different ethylene oxide (EO) chain lengths. For comparison with these nonionic surfactants, anionic surfactant, sodium alkyl sulfate (AS, C12), was chosen. After depositing stearic acid, the PET film was cleaned in aqueous surfactant solutions by applying stirring as a mechanical action for soil removal. The amounts of stearic acid deposited on the PET film before and after the cleaning were obtained by binary processing of microscopic images of the PET film surface, from which the removal efficiency was calculated. The surface tension γ and the contact angle on the PET film θ of the surfactant solution were measured by the pendant drop and the sessile drop method, respectively. For the nonionic surfactants, critical micelle concentration, cmc, and γ and θ above cmc decreased with decreasing EO chain length. The removal efficiency of stearic acid increased with increasing surfactant concentration and further increase in the removal above cmc was observed in the cases of AE and MEE with EO chain length of 10. The removal efficiencies obtained in all systems had good relation with both γ and θ, indicating that the penetration of the surfactant solution between stearic acid and the PET film in the contact zone was a dominant factor in the soil removal in the present system.

Dynamic Analysis of the Removal of Fatty Acid from a Pet Surface Using a Quartz Crystal Microbalance

“…AE was provided from Lion Corporation, Japan. The critical micelle concentrations (CMC) of AS and AE were determined to be 8.0 and 0.14 mmol/dm 3 , respectively, at 20°C by a surface tension measurement using the pendant drop technique in the previous study [7]. Similar values have been reported by other researchers for AS [26] and AE [27].…”

Application of Quartz Crystal Microbalance as a Tool for Detergency Evaluation of Fatty Acid Contamination in Aqueous Systems

“…The critical micelle concentration of SDS in the presence of 1.0 mmol dm 3 NaCl was determined to be 8.0 mmol dm 3 at 20 based on the surface tension measured by the pendant drop technique 14 .…”

Experimental Analysis of Detergency Phenomena and Investigation of a Next-generation Detergency System

“…The removal of stearic acid as a model oily soil from the PET film was investigated using a microscopic image analysis system 12 . Prior to the soil removal experiment, stearic acid was deposited on the PET film by spraying of its acetone solution.…”