Sprayable cellulose nanofibrils stabilized phase change material Pickering emulsion for spray coating application.

Phase change materials (PCM) have been increasingly used over the past decades in applications requiring thermal energy storage or maintaining temperature uniformity, in particular in the textile industry. Organic PCM is desired in temperature control, but it suffers from thermal leaking and unstable form during phase transition. Here, cellulose nanofibrils (CNFs) were used as emulsifiers to stabilize paraffin Pickering emulsion by ultrasonication. Results indicated uniform PCM emulsion particles of 4.2 ± 2.1 μm could be obtained using 0.8 wt% CNF suspension sonicated at 100%A and 7 mins with 2:8 paraffin to CNF ratio. The CNF-stabilized paraffin emulsion showed excellent long-term stability with unchanged particle size when stored at 45 °C for 28 days. In addition, differential scanning calorimetry (DSC) results showed high thermal stability after 51 heating-cooling cycles with high latent heat of 117.6 J/g. The CNF-stabilized paraffin emulsion can be facilely spray-coated onto fabric to prepare thermal regulating textile.