Stochastic Ultralow-Frequency Oscillations of the Luminescence Intensity from the Surface of a Polymer Membrane Swelling in Aqueous Salt Solutions.

Catherine A Galkina,Alexandr F Seliverstov,Alexandr S Dmitriev,Maria A Okuneva,Valery G Gryaznov,Oleg V Ovchinnikov,Oleg P Smoliy,Polina N Bolotskova,Nikolai F Bunkin,Elena V Bondarchuk,Igor F Turkanov,Valeriy A Kozlov

doi:10.3390/polym14040688

Abstract

Photoluminescence from the surface of a Nafion polymer membrane upon swelling in isotonic aqueous solutions and Milli-Q water has been studied. Liquid samples were preliminarily processed by electric pulses with a duration of 1 μs and an amplitude of 0.1 V using an antenna in the form of a flat capacitor; experiments on photoluminescent spectroscopy were carried out 20 min after this treatment. A typical dependence of the luminescence intensity, I, on the swelling time, t, obeys an exponentially decaying function. The characteristic decay time of these functions and the stationary level of luminescence intensity depend on the repetition rate of electrical pulses, and the obtained dependences are well reproduced. It transpired that, at certain pulse repetition rates, the dependence, I(t), is a random function, and there is no reproducibility. Stochastic effects are associated with a random external force of an electromagnetic nature that acts on a polymer membrane during swelling. The source of this random force, in our opinion, is low-frequency pulsations of neutron stars or white dwarfs.

Highlights

Introduction iationsNafionTM (C7 HF13 O5 S × C2 F4 ) consists of perfluoro-vinyl ether groups terminated with sulfonic groups on a tetrafluoroethylene (Teflon) backbone
The purpose of this study is to clarify the mechanisms of interaction of a polymer membrane with isotonic solutions with low-frequency electromagnetic radiation, which can be used in medical practice
We performed a number of experiments with photo-luminescent spectroscopy, where we studied in detail the range of repetition rates of electrical pulses from 5 Hz to 500 kHz with an interval of 5 Hz; if at certain

Summary

Introduction

NafionTM (C7 HF13 O5 S × C2 F4 ) consists of perfluoro-vinyl ether groups terminated with sulfonic groups on a tetrafluoroethylene (Teflon) backbone. While the sulfonic groups are essentially hydrophilic. While swelling in an aqueous media, a nanostructure consisting of cylindrical reverse micelles appears. 2–3 nm diameter form within the Nafion membrane; see [1] for more details. The majority of techniques, applied for Nafion studies, are focused on the study of the polymer bulk properties. Water adjacent to the swollen polymer surface has been explored, see recent works [7,8,9,10], and the monograph [11] describes experiments, in which a Nafion membrane is immersed in an aqueous suspension of colloidal microspheres

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