Synthesis of polymer nanogels by electro-Fenton process: investigation of the effect of main operation parameters

Abstract

Recently, electro-Fenton (EF) process has been shown as a promising, facile, effective, low cost and environmentally-friendly alternative for synthesizing polymer nanogels suitable as biocompatible nanocarriers for emerging biomedical applications. Here, the electrochemically-assisted modification of poly(vinylpyrrolidone) (PVP) by EF process was studied to assess the role of key operation parameters for a precise modulation of polymer crosslinking and its functionalization with [sbnd]COOH and succinimide groups. The dimensions of the nanogels, in terms of hydrodynamic radius (Rh) and weight-average molecular weight (Mw), can be tuned up by controlling the electrolysis time, current density (j) and PVP and Fe2+concentrations, as demonstrated via dynamic and static light scattering and gel permeation chromatography analysis. Using PVP at 0.25 wt.%, Fe2+at 0.5-1.0 mmol dmâ\u88\u923and low j, short treatment times induced intramolecular crosslinking with chain scission, allowing size reduction of PVP particles from 24 to 9â\u80\u9310 nm. Longer reaction times and higher PVP and Fe2+contents favored intermolecular crosslinking ending in Mwvalues higher than the initial 3.95 Ã\u97 105 g molâ\u88\u921. An excessive [rad]OH dose from a too high circulated charge (Q), i.e., too prolonged electrolysis time even at low j or too high j even for short time, promoted intramolecular crosslinking (Rh â\u88¼Â 10â\u80\u9312 nm) along with a very significant chain scission probably owing to the loss of mobility of the three-dimensional nanogel network. In conclusion, EF allowed transforming the architecture of linear, inert PVP chains into a functionalized nanogel with [sbnd]COOH and succinimide groups that have great potential for further conjugation

Facile crosslinking of poly(vinylpyrrolidone) by electro-oxidation with IrO2-based anode under potentiostatic conditions

“…The spectroscopic investigation of the chemical structure of all fabricated polymer nanogels was carried out by FT-IR analysis. No evident oxidation of the parent chemical structure was detected, in contrast to the intensive modification observed in our previous work based on EF process [26]. This suggests that the presence and the action of H 2 O 2 and O 2 in the EF process may contribute very significantly to the formation of oxygen-rich functional groups.…”

“…This means that intermolecular crosslinking is favored within this high potential region, which can be explained from the larger number of hydroxyl radicals that lead to a higher concentration of independent macroradicals. In conclusion, this behavior indicates that electro-oxidation with DSA ® can be used, unlike electro-Fenton process [26], mainly to enhance the dimensions of PVP particles, ending in more voluminous coils.…”

“…Within this context, the electrochemical technology offers a promising, alternative green route for the • OH -based production of high purity PVP nanogels. In particular, we have recently demonstrated for the first time the promotion of electrochemical crosslinking in aqueous PVP solutions by means of electrochemical advanced oxidation processes (EAOPs) like electro-oxidation (EO) and electro-Fenton (EF) [25,26]. Both methods allow the generation of hydroxyl radicals on site in a controlled manner upon accurate modulation of the electrolysis conditions [27,28].…”

“…Both methods allow the generation of hydroxyl radicals on site in a controlled manner upon accurate modulation of the electrolysis conditions [27,28]. Main operation parameters have been optimized for EF, leading to size reduction of PVP nanoparticles down to 9 nm and functionalization with -COOH and succinimide groups [26]. In contrast, the performance of EO has not been investigated in detail yet.…”

Groundwater Treatment using a Solid Polymer Electrolyte Cell with Mesh Electrodes

“…These are considered environmentally friendly treatments that are easy to operate and maintain, also being safe, readily scalable and relatively cost‐effective, typically involving the use of ambient pressure and temperature. Electrochemical oxidation (EO),, electro‐Fenton (EF),, and photoelectro‐Fenton (PEF),, are ubiquitous EAOPs for effective wastewater treatment in which organics pollutants are mainly destroyed by the strong oxidant hydroxyl radical ( . OH).…”