Ultra-Low-Frequency Oscillations of Luminescence Intensity for a Polymer-Membrane in Aqueous Salt Solutions. Dependence on the Isotopic Composition

The photoluminescence from the surface of a polymer Nafion membrane upon its swelling in isotonic aqueous solutions and doubly distilled water has been studied. Liquid samples were previously subjected to electrical pulses with widths of 1 µs and amplitudes of 0.1 V, generated by an antenna shaped as parallel-plate capacitor. The photoluminescence spectroscopy experiments were performed 20 min after the treatment. The typical dependence of the luminescence intensity on the swelling time t can be presented by an exponentially decreasing function. The characteristic decay time of these functions and the steady-state level of luminescence intensity depend on the repetition rate of electrical pulses; the experimental dependences are reproduced well. It was found that, at some pulse repetition rates, the time dependence of the luminescence intensity I ( t ) is a random function, and there is no reproducibility. Stochastic effects are related to the random external force of electromagnetic nature, which acts on a polymer membrane upon swelling. In our opinion, this random force is caused by low-frequency pulsations of neutron stars or white dwarfs.