Encapsulation is an important process for protect phase change materials (PCMs) from the outside environments and prevent leakage and loss of PCMs in frequent phase transition process. The encapsulation of PCMs using polyelectrolyte (PEL) multilayer as capsule shell is a good choice because this method uses a low concentration of non-toxic chemical reagents and low treatment temperature, resulting in cost and energy-saving and eco-friendly process. However, the thickness of PEL multilayer shell and characteristic of PEL layer were considered to play a significant influence on thermal properties of PEL encapsulated n-octadecane (PEL-en-Oc) nanocapsules, i.e. latent heat and thermal stability. Therefore, the effect of number of PEL shell layers on thermal properties of PEL-en-Oc nanocapsules was studied using two types of PEL, i.e poly (diallyldimethylammonium chloride) (PDDA) cationic polyelectrolyte and poly 4-styrenesulfonic acid (PSS) anionic polyelectrolyte. The PEL-en-Oc nanocapsules were prepared by stepwise adding PDDA and PSS solutions into the nanoemulsion of n-octadecane, resulting in the formation of PELx1-en-Oc, PELx2-en-Oc or PELx3-en-Oc nanocapsules with single, double and triple shell layers, respectively. The zeta-potential results revealed the successful coating of stepwise assembled PEL on the surfaces of n-octadecane droplets, in which the average particle sizes of PEL-en-Oc nanocapsules were in the range of 154 – 204 nm. The increase of number of PEL shell layers could increase the thermal stability of PEL-en-Oc nanocapsules, but decrease the latent heat of n-octadecane in nanocapsules. The PELx3-en-Oc nanocapsules with 118 J/g of latent heat of fusion exhibited the highest thermal stability.

Effect of polyelectrolyte multilayers shell on thermal properties of n-octadecane phase change material nanocapsules

251st National Meeting (2016)

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