Solid-Contact Ion-Selective and Reference Electrodes Covalently Attached to Functionalized Poly(ethylene...

Area of Science:

• Materials Science
• Electrochemistry
• Sensor Technology

Background:

• Traditional ion-selective electrodes (ISEs) often use bulky designs with aqueous inner solutions.
• Recent trends focus on planarizable solid-contact electrodes for point-of-care and wearable applications.
• A major limitation of current solid-contact ISEs is membrane delamination from the substrate under mechanical or thermal stress, reducing sensor lifetime.

Purpose of the Study:

• To develop a robust sensing platform that prevents membrane delamination in solid-contact ion-selective electrodes.
• To create ion-selective and reference electrodes with enhanced long-term performance and mechanical stability.
• To demonstrate a versatile method for covalently attaching sensing and reference membranes to various plastic substrates.

Main Methods:

• Designed a sensing platform using poly(ethylene terephthalate) (PET) substrates.
• Covalently attached polyacrylate-based sensing membranes and polymethacrylate-based reference membranes to functionalized PET via photopolymerization.
• Prepared H+- and K+-selective electrodes and reference electrodes using ionophore- and ionic-liquid-doped membranes.

Main Results:

• Successfully achieved covalent attachment between the substrate and the membranes, preventing delamination even under repeated mechanical stress.
• Prepared H+- and K+-selective electrodes exhibited highly selective responses with Nernstian slopes.
• Reference electrodes provided stable, sample-independent reference potentials across a broad range of electrolyte concentrations.

Conclusions:

• Covalent attachment of sensing and reference membranes to plastic substrates offers a highly promising solution to the long-standing problem of membrane delamination in ISEs and field-effect transistors.
• This approach significantly improves the long-term performance and reliability of solid-contact electrodes.
• The method is adaptable to various polyester, polyamide, and polyurethane materials, broadening its applicability.