Abstract
High-resolution 13C CP/MAS NMR spectra of poly(aspartic acid) (PAA) and its sodium salt (PAANa) obtained with various neutralization numbers, n (=[COONa]/[COOH+COONa], where [ x] is the molar concentration of x), have been measured over a wide range of temperatures, in order to elucidate the conformation and its stability in the solid state. From these experimental results it was found that, at room temperature (25°C), the main chain of PAA takes a mixture of right-handed α ( α R)-helix, ω-helix and β-sheet forms and, with an increase in temperature from 25°C to 180°C, changes from α R-helix form and ω-helix form to β-sheet forms. On the other hand, the main chain of PAANa takes the right-handed α R-helix form in the temperature range from 25°C to 210°C. With a decrease in the neutralization number, PAANa changes to PAA and the NMR spectra are correspondingly changed.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
