In a relatively small temperature interval, tan δ-curves, recorded at different frequencies, evolved in a pattern which is typical for a physical gelation.
Because we inspected a relatively small temperature interval, we assumed that Δ H° and Δ S° are fairly temperature-independent.
Mehling and Cabeza have proposed the stored heat over a series of small temperature intervals (as opposed to a single (Q_mathrm{stored}) value for the entire transition region) as a convenient representation of the storage capacity of a PCM in a given temperature region [1].
In particular, the application of phase change materials (PCMs) is considered as an effective and efficient approach to thermal energy storage because of the high latent heat storage capacity at small temperature intervals.
In the past decade, the interest in phase change materials (PCMs) has grown significantly due to their ability to store large amounts of thermal energy in relatively small temperature intervals.
In particular, the application of phase change materials (PCMs) is considered as an effective and efficient approach to thermal energy storage because of the high latent heat storage capacity at small temperature intervals (Zeng et al. 2013; Zhang et al. 2013; Tang et al. 2015; Cai et al. 2015).
Does a small temperature rise actually matter?
There is also evidence of hysteresis between the latter two temperatures as can be seen from the heating and cooling traces, which was confirmed in a second cooling and heating run with smaller temperature intervals.
PHEMA PEtOx and PHPA PEtOx hydrogels exhibited a large and reversible swelling deswelling process, whereas the volume changes in PMMA PEtOx swollen networks were small and occurred in a broad temperature interval.
