Water polarisation transfer (WPT). Water polarisation transfer is an NMR technique that allows to obtain the hydration profile of polymer fibres. It does so by using a T2 filter to remove the transverse magnetisation of the surface of the fibres and leaving water polarisation to then be transferred to the polymer by spin diffusion, chemical exchange and NOE. By representing the normalised growth of water polarisation against the √ mixing time, the hydration profile of each carbon is obtained.  The parameters for the experiment were:  NS was 256 scans, DS was8 scans, D1 was 10 s, P15 was 500 us. One spectrum was run with no T2 filter (D20) to be used a reference sample. One spectra was ran with a T2 filter but with no mixing time to check for effectiveness of T2 filter. The rest were subsequently had a D20 of 2 Ms and a series of D8 that ranged from 1Ms to 324 Ms. All WPT experiments were conduced in 293 K.