Quantitative NMR characterization of long-range chain dynamics prior to reptation: Polyethylene-oxide

The thorough analysis of the transverse magnetic relaxation of protons, att ached to highly entangled polyethylene-oxide chains in the melt, reveals tw o striking chain-length dependent properties; these are interpreted from th e description (reminiscent of the Rouse model) of the long-range chain dyna mics supposed to occur prior to the reptation motion. Experimental results are well matched by this specific NMR approach which accounts for the novel properties and provides the monomeric friction coefficient and the termina l relaxation time, over the molecular weight range 65K to 760K.