The “recipe” to know the type of dynamics “before” applying the diffusion models: application in water-soluble polymer

Motivation: Currently, diffusion models are applied without knowing the type of dynamics a priori. The risk is to quantify parameters that do not reflect the dynamics of the system. Goal(s): Here we show that it is possible to carry out a preliminary check to know the type of dynamics a priori. Approach: We tested our recipe in 40% w/w Poly(ethylene glycol) (PEG) water-solution using PGSTE at different big Delta, little Delta and gradient strength. Results: We showed that both water and PEG CH2 showed a Super-Statistic dynamic while the dynamics of the OH tail of PEG is an unknown process. Impact: Currently, diffusion models are applied without knowing the type of dynamics a priori. We introduce a recipe to know the type of dynamics. This method avoids the quantification of diffusion-parameters that do not reflect the true diffusion of the system.