Preparation And Properties Of Phase Change Microcapsules Based On Pickering Emulsion

Phase change material?PCM?has played an important role as an important component of sustainable energy systems.Among them,phase change microcapsules?Microencapsulated phase change materials,micro PCMs?are one of the most widely used application forms.The shell material is used to encapsulate the internal core material to maintain its stable properties and enhance heat transfer.In this study,in the structural design of phase change microcapsules,Pickering particle stabilizer was introduced,and phase change microcapsules were prepared by using Pickering emulsion template method.The introduced functional particles can not only serve as phase change microcapsules as Pickering particle stabilizers,but also improve the performance of the microcapsule shell.The selected Pickering particles are mainly carbon-based materials with good thermal conductivity,impermeability,and mechanical properties,including graphene?Gr?and nanodiamond?ND?.The main contents of this paper include:?1?Pn@Gr/MF phase change microcapsules were prepared by using Gr as the Pickering particle stabilizer and polymer melamine resin as the shell material by the Pickering emulsion template method and in-situ polymerization method.The effects of different concentrations of Gr and different core-shell ratios on the various properties of Pn@Gr/MF phase change microcapsules during the preparation process were studied.When the concentration of Gr is 2 g/L,the various properties of phase change microcapsules?microPCMs-2Gr?are the best,the leakage rate is reduced by 93.20%,and the light-to-heat conversion efficiency is about 90.7%.For different core-shell ratios,the best overall performance is that the core-shell ratio is 4:1,and the latent heat of phase transition is as high as 204.0 J?g^-1.?2?Pn@ND/MF phase-change microcapsules with superhydrophobic properties were prepared by using ND as the Pickering particle stabilizer,and the morphology of Pn@ND/MF phase-change microcapsules with different contents of ND,Thermal conductivity,leakage,superhydrophobic and other properties.With the increase of ND,the thermal conductivity and anti-seepage performance have been improved.The thermal conductivity of microPCMs-6ND reached 0.782 W?m^-1?K^-1,and the leakage rate was 0.71%in 180 minutes.The phase change enthalpies of Pn@ND/MF phase change microcapsules are all above 200 J?g^-1,have good latent heat capacity for phase change,and the contact angles CA are all above 150°,which has a certain superhydrophobicity.