Development of stopped-flow hyper-CEST NMR method on recirculating hyperpolarization system as applied to void space analysis in polymers.

Abstract in brief

• The text discusses a new NMR technique called hyperCEST combined with recirculating hyperpolarization, stoppedflow, and subtraction modes to improve the detection of small or hidden signals related to void spaces in polymers, which traditional methods struggle with due to low sensitivity.
• This method was successfully applied to analyze void spaces in polymers like cellulose nanofiber, silk fibroin, and thermoplastic polyurethane, providing useful information about their structural characteristics by determining the chemical shifts of weak signals.
• The subtraction mode is highlighted as particularly effective for quickly identifying whether specific weak signals are present or absent, demonstrating the potential of this approach for future research in exploring subtle features within polymer materials.]