Interaction of Pyrene-Labeled Poly(ethylene imine) with Sodium Dodecyl Sulfate in Aqueous Solution

Abstract

The interaction between pyrene-labeled poly(ethylene imine) (PEI−Py), a hyperbranched polymer, and the anionic surfactant sodium dodecyl sulfate (SDS) in aqueous solution was studied using steady-state fluorescence measurements. Fluorescence experiments were carried out with PEI−Py containing approximately one Py group per 900 monomer polymer units (PEI−Py/900) at two different pH and at two polymer concentrations. When SDS was added to the PEI−Py/900, at both pH 6.6 and pH 10, the monomer fluorescence I M increased significantly, with a much less pronounced change in the excimer emission (I E). In the absence of SDS, the monomer intensity is substantially reduced due to quenching of Py* by secondary and tertiary amino groups of the polymer, whereas the excimer emission is less affected. The increase in I M with increasing SDS concentration indicates that SDS molecules protect Py* from quenching, through formation of polymer-bound micelles formed at the sites of the Py groups. In contrast, I E remains practically unchanged (0.3 wt % PEI, pH 6.6) or decreases. The decrease in I E is attributed to disruption of Py aggregates upon their binding to SDS.

Supramolecular complexes formed by the association of poly(ethyleneimine) (PEI), sodium cholate (NaC) and sodium dodecyl sulfate (SDS)

“…5,33,37,38,40,41 They are undoubtedly useful in determining key parameters, such as cmc and cac. The fluorescent probe pyrene has five fluorescent bands and the ratio between its I 1 (372.8 nm) and I 3 (384.0 nm) bands is sensitive to small changes in the environmental polarity.…”

“…Recently, SDS-PEI complexes have been investigated. [31][32][33][34][35][36] explored the influence of the pH on the binding properties of SDS in linear and branched PEI. Winnik et al 31,33,34 studied the influence of the pH values and surfactant concentration on the SDS-PEI interaction through conductivimetry, light scattering, nuclear magnetic resonance (NMR), microcalorimetry and electrical conductivity.…”

“…[31][32][33][34][35][36] explored the influence of the pH on the binding properties of SDS in linear and branched PEI. Winnik et al 31,33,34 studied the influence of the pH values and surfactant concentration on the SDS-PEI interaction through conductivimetry, light scattering, nuclear magnetic resonance (NMR), microcalorimetry and electrical conductivity. Meszaros et al 35 also studied this system and demonstrated that the interaction occurs in two steps: firstly there is a specific binding of dodecyl sulfate ions (in the monomer form) to protonated amine groups (evidenced by the increase in pH) and, secondly, a cooperative interaction of a hydrophobic nature occurs.…”

A novel fluorescence probe for micellization of amphiphilic molecules in water based on intramolecular exciplex formation

“…Self-quenching of the monomer emission increases with increasing concentration of the probe due to the fact that the probe is highly hydrophobic and has very limited solubility in water. Thus, microcrystals of the probe may form, resulting in self-quenching of the monomer fluorescence and enhancement of the exciplex fluorescence 6,15) . This leads to a larger apparent value for I e /I m .…”

Solution Behavior of Hydrolyzed Gradient Methyl/Phenyl Oxazoline Copolymers and Complexation with DNA

“…[ 37,[41][42][43][44] Fluorescence spectroscopy with pyrene as probe is a well-known technique to study the association behavior of copolymers. [ 45 ] Fluorescence experiments can provide important information about the local polarity and fl uidity of the nanoassemblies. It is also known that the ratio of the emission intensities of the vibronic bands 1 and 3 ( I 1 / I 3 ), which is sensitive to the local polarity of the pyrene environment, can be utilized in order to obtain an estimation of the number and/or size of hydrophobic microdomains present in the solution.…”