Waterproof Phase Change Material with a Facilely Incorporated Cellulose Nanocrystal/Poly(N-isopropylacrylamide) Network for All-Weather Outdoor Thermal Energy Storage

Abstract

The incorporation of porous supporting materials to prepare shape-stable phase change materials (PCMs) is of great interest in recent years. However, extensive reported composite PCMs are shape-stable in the air atmosphere but neglected in the water environment. To develop shape-stable and waterproof PCMs is important for their outdoor applications but challenging. Herein, we report a novel cellulose nanocrystal/poly­(N-isopropylacrylamide) (CNC/PNIPAM) gel-supported hexadecanol (H-anol) PCM with good thermal storage properties and excellent shape stability in both air and water environments. The CNC/PNIPAM hydrogel is prepared through an ultraviolet-induced CC cross-linking reaction, and its physical structure and mechanical properties are well characterized. H-anol is then directly immerged into the CNC/PNIPAM alcogel by a facile and low-cost solvent-exchange strategy. The mechanism of the solvent-exchange strategy has been established. Because of the temperature-sensitive hydrophilic/hydrophobic transform behavior of the CNC/PNIPAM network, the CNC/PNIPAM/H-anol PCM displays excellent shape stability in a water environment by forming a dense hydrophobic surface, providing it with great potential in all-weather thermal energy storage applications.

Scalable Flexible Phase Change Materials with a Swollen Polymer Network Structure for Thermal Energy Storage

“…Effective thermal management is of crucial significance to prevent the overheating problem of electronics such as integrated systems, batteries, laser instruments, radars, and flexible devices. − Recently, high-performance organic solid–liquid phase change materials (PCMs) capable of storing and releasing energy in the form of latent heat have attracted increasing attention. − In addition to thermal management, the utilization of solar energy associated with PCMs is a promising way to develop a green energy conversion supply chain. However, the application of organic PCMs in the thermal management of cutting-edge technologies has been significantly hampered by their low thermal conductivity ( k , 0.2–0.4 W/mK) and liquid leakage, restricting energy charging/discharging rates and threatening the safety of devices and energy conversion systems. − …”

Exploring Next‐Generation Functional Organic Phase Change Composites

“…Superhydrophobic coatings were sprayed on the surface of composite PCMs to fabricate superhydrophobic phase change monoliths with low moisture absorption and self‐cleaning properties (Figure 3a–c), making the composite PCMs unaffected in a wet environment. [ 72 ] Furthermore, Yang et al., [ 40 ] reported a waterproof phase change composite prepared by incorporating a cellulose nanocrystal‐poly(N‐isopropylacrylamide) (CNC‐PNIPAM) network into hexadecanol using a facile solvent‐exchange strategy (Figure 3d). The resulting composite PCMs exhibited considerable TES capacity and good shape stability in both air and water environments (Figure 3e), presenting great potential for applications in all‐weather outdoor TES.…”

“…b) Reproduced with permission. [ 40 ] Copyright 2020, American Chemical Society. c) Reproduced with permission.…”

“…Copyright 2021, American Chemical Society. b) Reproduced with permission [40]. Copyright 2020, American Chemical Society.…”

Polymer Encapsulation Strategy toward 3D Printable, Sustainable, and Reliable Form-Stable Phase Change Materials for Advanced Thermal Energy Storage

“…31 Recently, the polymeric form-stable PCMs based on PEG were reported to exhibit the recyclability via the comprehensive effect of hydrogen bonds, ionic bonds, and transesterification. 22 Frustratingly, there are two major issues in PEG-based systems: one is the water solubility of PEG, which makes form-stable PCMs difficult to be used in humid environments; 32 another is the inherently low productivity due to the low-activity polycondensation and multistep synthetic route. Accordingly, it is particularly desirable to design novel polymeric form-stable PCMs with the all-weather usage ability, facileness, high efficiency, and green preparation process as well as degradability/recyclability.…”