2.2. NMR transverse relaxation measurements
The stripes were placed into a cylindrical glass tube (18 mm in
diameter). The relaxation measurements were performed on a Niumag
Pulsed NMR analyzer (PO001, Niumag Corporation, Shanghai,
China) with a resonance frequency for protons of 22.7 MHz at
32 C. Transverse relaxation was measured using the Carr-Purcell-
Meiboom-Gill sequence (CPMG) (Bertram, 2004), with a svalue
(time between 90 pulse and 180 pulse) of 100 ls, and the
lengths of the pulses were 19.0 and 38.0 ls, respectively. The repetition
time between two scans was 3 s. Data from 4000 echoes
were acquired as 4 scan repetitions and analyzed by a multi-exponential
model under the program of the MultiExp Inv Analysis
(Version 4.08, Niumag Corporation, and Shanghai, China).