Probing the balance of Telechelic Polymers Bridging and Screened-Coulomb Interactions in Microemulsion System

Abstract

The structural properties of neutral oil-in-water (O/W) microemulsions nanodroplets in the presence of telechelic polymers PEO modified with two hydrophobic end functions (PEO- 2m) were studied by Small-Angle Neutron Scattering (SANS). We show that the unknown attractive interaction introduced by the addition of PEO-2m, can could be balanced by a known repulsion interaction due to the addition of a cationic surfactant Cp +, which causes a progressive transformation of the bridges connecting the nanodroplets into loops. For this, we compute the structure factor S(q) with an effective pair potential, using the Ornstein Zernicke (OZ) integral equation approach with the Hypernetted Chain (HNC) closure relation. Generally, the agreement between the neutron scattering spectra and the numerical study is reasonable and allows a detailed description for each sample.

A study of the structure and thermodynamics of non-ionic microemulsion droplets: Integral equation methods (IEs) and molecular dynamics simulation (MD)

“…Concerning the impact of added polymers on MEs droplets interactions; in the dilute case (ϕ = 6.8%), the addition of PEO-m induced a steric repulsive interaction, while PEO-2m induced a bridging attractive interaction. Conversely, in the concentrated case (ϕ = 13.3%), both polymers amplified the repulsive interactions between microemulsion droplets [5][6][7][8][9].Similarly, Ahfir et al examined the dynamics of the TX100 system, including relaxation modes and diffusion coefficients, as function of ϕ [10]. Furthermore, the authors explored the structure and dynamics of mixed systems consisting of charged MEs covered with telechelic polymers (PEO-m, PEO-2m), using a combination of IEMs and MD simulations.…”

Dynamic properties of decane/water microemulsions decorated with hydrophobically modified PEO Polymer (PEO-C12): A molecular dynamics simulations study

“…The integral equation method (IEM) was used for the structural study: The presence of the PEO-2 C12 introduces an effective attractive interaction between droplets, while the PEO-C12 introduces a repulsive interaction. Relaxation modes with diffusion coefficients were determined as a function of volume fraction Φ, size polydispersity and charge polydispersity [5][6][7][8][9][10][11][12][13].…”