Vertical-Flow Paper Sensor for On-Site and Prompt Evaluation of Chloride Contamination in Concrete Structures

Abstract

Corrosion occurring in reinforced concrete has turned into a primary concern of the current century, concrete being the most ubiquitous and predominant material used in the construction industry. Among the many interrelated processes that trigger corrosion of metallic reinforcements, the penetration of chloride ions into the concrete matrix is the most insidious threat. Herein, we developed the first electrochemical device entirely made of paper that allows for the direct, prompt, and noninvasive evaluation of free chloride ion contamination in concrete-based constructions. Our device is based on a three-layer wax-modified filter paper, consisting of two Ag/AgCl screen-printed electrodes that are interfaced by a junction pad in a sandwich-like configuration. Filter paper allows for generating a vertical-flow potentiometric device capable of measuring the electrochemical potential between two solutions containing different concentrations of chloride ions, which are separately drop-cast on the top and bottom layers. After demonstrating the analytical performance of the device, the same principle was applied to the evaluation of the chloride contents in different concrete samples, exploiting paper as a suitable interfacing material for potentiometric measurements on the cement solid surface. Laboratory-prepared concrete samples with known chloride contents were first assessed, and then, the paper-based verticalflow device was applied to real concrete structures at the Giacomo ManzùMuseum (Ardea, Italy) for the evaluation of chloride contamination caused by the proximity to the seaside. The capability of our device to provide timely warning of the risk conditions of concrete-based artifacts was demonstrated.

Progress in Sensors for Monitoring Reinforcement Corrosion in Reinforced Concrete Structures—A Review

“…Initially, the sensors embeddable into concrete were chloride-selective electrodes, for instance, silver/silver chloride electrodes [25,[87][88][89]. Ion-selective electrodes are chemically stable in aggressive environments and easy to manufacture.…”

Paper card-like electrochemical platform as a smart point-of-care device for reagent-free glucose measurement in tears

“…– is used to print sensors for detecting the parameters and the target analyte in the solid sample, like the potential, pH, and chloride content in concrete-based structures; 18,19…”

“…-serves as a reactor in which the nanomaterial was synthesized, allowing for nanomaterial-decorated paper ready to be used as a support, already modified with nanomaterials, for printing the electrochemical cell; 13 -is used as a reservoir to contain the reagents by loading the paper network with a few mL of the reagent solution. In that case, after the solvent volatilization, the reagents remain inside the cellulose network, and the addition of the liquid sample dissolves them, delivering a reagent-free device; 14 -is used as a preconcentrator by adding several aliquots of the sample through several steps by increasing the sensitivity of the measurement easily; 15 -allows for the direct sampling of the analyte in aerosol without no additional sampling device, overcoming the limitations of the polyester-or alumina-based printed electrochemical sensors able to measure only liquid samples; 16,17 -is used to print sensors for detecting the parameters and the target analyte in the solid sample, like the potential, pH, and chloride content in concrete-based structures; 18,19 -easily collects sweat by using the capillarity properties of paper, even when combined with a Kapton-based sensor. 20 In this communication, we demonstrate for the first time that paper serves as a card to insert in polyvinyl chloride (PVC)based electrochemical cells for developing novel point-of-care devices.…”

Photothermal-Reagent-Triggered Visual Thermoresponsive and Quantized Photoelectrochemical Dual-Signal Assay

“…Over the recent period, paper-based flexible sensors have been widely used in the point-of-care testing (POCT) field; they are expected to become a greatly promising candidate tool for in vitro detection. , Its popularity lies in the inherent advantages of inexpensiveness, rapidness, light weight, and user-friendliness, especially suitable in family disease diagnosis. , In addition, the integratable origami-chip platform makes it possible to the migration of a functional biological matrix at the surface by intrinsic hydrophilic fluidic pathways, thus ensuring efficient interworking of the zones . Currently, various techniques such as fluorescence, chemiluminescence, and electrochemistry have been introduced into the origami chip for clinical monitoring and quantitative screening in the POCT field.…”