Design and Fabrication of Epichlorohydrin-Cross-Linked Methyl Cellulose Aerogel-Based Composite Materials for Magnetic UV Response Light-to-Heat Conversion and Storage.

The collection, storage, and use of energy and information are important issues for overcoming the global energy shortage while satisfying the demand for information transmission. This research reports a nano-Fe3O4 and erythritol (ER)-functionalized, cross-linked methyl cellulose aerogel (MC-EP) composite that has the characteristics of phase-change energy storage as the magnetic and ultraviolet responses requisite for light-to-heat conversion and storage. The nano-Fe3O4 particles in MC-EP-ER-75 were fixed and filled into pore structures in MC-EP. ER was used to form an effective combination with MC-EP. The addition of nano-Fe3O4 compensated for the low thermal conductivity of ER. The MC-EP-ER-75 was able to store solar radiation-induced energy due to the loading of ER at a photothermal conversion efficiency of 79.67% and a light-to-heat conversion efficiency of 79.67%. The results of thermal stability (TGA) analysis showed that MC-EP-ER-75 was thermally degraded acceptably below 200 °C. The differential scanning calorimetry curve and latent heat values (melting/crystallization enthalpies of 314.8 and 197.9 J/g, respectively) of MC-EP-ER-75 did not change after 100 cycles. In addition, it exhibited excellent saturation magnetization, super-paramagnetism, and ultraviolet shielding, as well as a rapid response to the ultraviolet and magnetic fields. This provided a way to prepare light-to-heat conversion-storage-release materials and ultraviolet-magnetic sensors that can be used in renewable resources.

Shape-stabilized composite phase change film with good reversible thermochromic properties fabricated via phase inversion-assisted impregnation.

In this study, the regenerated porous cellulose film (LD) was properly prepared by dissolving cellulose in a LiCl/DMAc solvent though a simple phase inversion method. LD has a porous structure, good mechanical properties and great thermal stability. In order to form a shape-stabilized reversible thermochromic phase change film (DTLD), a reversible thermochromic compound (DTBC) was added into the LD by simple vacuum impregnation. The effect of the weight ratio of 1-dodecanol/tetradecanol complex solvent (3 : 7, 2 : 8, 1.5 : 8.5 and 1 : 9) on the phase change properties was investigated. DTLD (1.5 : 8.5) showed the highest latent heat storage of 174.00 J g-1 with the suitable phase change temperature at 37.5 °C. The low thermal conductivity of DTLD (1.5 : 8.5) at 10 °C (50 °C) was 0.396 ± 0.004 W m-1 K-1 (0.408 ± 0.002 W m-1 K-1). The color of DTLD (1.5 : 8.5) can change reversibly between colorless and blue as temperature changes. Melting-cooling tests after 100 cycles indicated that DTLD (1.5 : 8.5) has a high latent heat storage capacity of 169.65 J g-1. A shape-stable reversible thermochromic phase change composite assembled from a regenerated porous cellulose membrane as a support matrix is expected to be applied to the field of thermal energy storage.