Voronin Denis, Mendgaziev Rais, Sayfutdinova Adeliya, Kugai Maria, Rubtsova Maria, Cherednichenko Kirill, Shchukin Dmitry, Vinokurov Vladimir
Department of Physical and Colloid Chemistry, National University of Oil and Gas "Gubkin University", 119991 Moscow, Russia.
Department of Chemistry, Stephenson Institute for Renewable Energy, University of Liverpool, Liverpool L69 7ZD, UK.
Materials (Basel). 2022 Dec 21;16(1):29. doi: 10.3390/ma16010029.
Phase-change materials (PCMs) attract much attention with regard to their capability of mitigating fossil fuel-based heating in in-building applications, due to the responsive accumulation and release of thermal energy as a latent heat of reversible phase transitions. Organic PCMs possess high latent heat storage capacity and thermal reliability. However, bare PCMs suffer from leakages in the liquid form. Here, we demonstrate a reliable approach to improve the shape stability of organic PCM -octadecane by encapsulation via interfacial polymerization at an oil/water interface of Pickering emulsion. Cellulose nanocrystals are employed as emulsion stabilizers and branched oligo-polyol with high functionality to crosslink the polyurethane shell in reaction with polyisocyanate dissolved in the oil core. This gives rise to a rigid polyurethane structure with a high density of urethane groups. The formation of a polyurethane shell and successful encapsulation of -octadecane is confirmed by FTIR spectroscopy, XRD analysis, and fluorescent confocal microscopy. Electron microscopy reveals the formation of non-aggregated capsules with an average size of 18.6 µm and a smooth uniform shell with the thickness of 450 nm. The capsules demonstrate a latent heat storage capacity of 79 J/g, while the encapsulation of -octadecane greatly improves its shape and thermal stability compared with bulk paraffin.
相变材料（PCMs）因其在建筑物应用中能够缓解基于化石燃料的供暖问题而备受关注，这是由于其作为可逆相变潜热的热能响应性积累和释放。有机相变材料具有高潜热存储能力和热可靠性。然而，裸露的相变材料存在液态泄漏问题。在此，我们展示了一种可靠的方法，通过在皮克林乳液的油/水界面进行界面聚合封装来提高有机相变材料十八烷的形状稳定性。纤维素纳米晶体被用作乳液稳定剂，具有高官能度的支化低聚多元醇与溶解在油核中的多异氰酸酯反应交联聚氨酯壳。这产生了具有高密度聚氨酯基团的刚性聚氨酯结构 。通过傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）分析和荧光共聚焦显微镜证实了聚氨酯壳的形成以及十八烷的成功封装。电子显微镜显示形成了平均尺寸为18.6 µm的非聚集胶囊，以及厚度为450 nm的光滑均匀壳。这些胶囊的潜热存储能力为79 J/g，而与块状石蜡相比，十八烷的封装极大地提高了其形状和热稳定性 。
