Probing pore-structure within porous polymer particles by NMR

2. Sample preparation and experimental procedure The polymer particles were prepared by Dynal Biotech and pre-saturated with water before packed into 10 mm NMR tubes, and sealed. All NMR measurements were performed on a 23.5 MHz MARAN Ultra NMR instrument. The spin-spin relaxation time (T2) was determined using a CPMG pulse sequence with; 2τ = 60 μs, π/2 rf-pulse = 2.15 μs, dwell time = 0.1 μs, dead time = 5μs, number of transients = 64 and time delay between successive scans = 10 s. The temperature was changed at a rate of 8 K/hour.