Step-by-step from amorphous phosphate to nano-structured calcium hydroxyapatite: monitoring by solid-state ¹H and ³¹P NMR and spin dynamics

Abstract

The solid-state 1H, 31P NMR spectra and cross-polarization (CP MAS) kinetics in the series of samples containing amorphous phosphate phase (AMP), composite of AMP + nano-structured calcium hydroxyapatite (nano-CaHA) and...

Solid-state NMR study of spin dynamics and local disorder in smart polymers: PDMAEMA

“…The topic of CP kinetics, i. e. the dependence of CP signal intensity I(t) on the contact time (t), was reviewed and discussed in Refs. [1,6,25]. However, as it was noted in Ref.…”

“…However, as it was noted in Ref. [6], the kinetic equation originally derived by Naito and McDowell [24] is incorrect in the presence of T 1ρ relaxation. In the present work, the correct solution derived by Hirschinger and Raya [26] was used.…”

“…, and the brackets 〈…〉 AA mean the angular averaging [6,29]. The cosine-oscillation frequency b (Eq.…”

“…Equation ( 1) was successfully applied for 1 H-31 P CP MAS build-up curves in amorphous phosphates [6]. However, the I-I * -S model considers an I * -S pair.…”

“…The processing of CP kinetic data, i.e. the consideration of the time evolution (contact time) of communication between spins, provides the rates of spin-diffusion and spin-lattice relaxation, the profiles of distribution of dipolar coupling and some other parameters accounting for the effective sizes of spin clusters [4][5][6]. Hence, it is a powerful method studying fine structural details and dynamics in advanced complex materials and polymers among those [7][8][9][10].…”