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ToolsLascelles, Elliot, Alcock, Keith M., Ravotti, Rebecca, Palacios, Anabel, Navarro, Helena, O'Rourke, Dominic, Panter, Jack and Landini, Stefano (2026) Leakage-Proof PEG Composites via Water-Based Processing of Algal α-Cellulose Nanofibrils for Sustainable Thermal Energy Storage. In: Proceedings of the 11th World Congress on Momentum, Heat and Mass Transfer (MHMT 2026). Avestia, Paris.
Full text not available from this repository. (Request a copy)Abstract
The advancement of sustainable thermal energy storage composites through green components and environmentally-responsible manufacturing methods is essential for future energy systems. Solid-liquid phase change materials (PCMs) are promising candidates, delivering high energy density through structural transformations and enabling operational specificity due to their defined phase-change temperatures. However, the practical application of solid-liquid PCMs is constrained by leakage and volume expansion during melting. Conventional strategies for shape-stabilising PCMs rely either on encapsulation, which is prone to failure from volume-induced rupture and introducing a thermal barrier, or on supporting matrices such as porous silica and fibre scaffolds. These approaches, while effective at suppressing leakage, demand high mass fractions of supporting material at a minimum of 20–25% [1]. Ultimately this, coupled with the incorporation of toxic fillers [2], diminishes the composite energy density and sustainability. A further limitation of common supporting matrix strategies, such as porous silica frameworks and sisal wood-derived cellulose scaffolds, is the fabrication process depending on forming macro-scale structures that are infiltrated with PCM by vacuum impregnation. This process is not only energy-intensive but also underutilises the available nanostructure: the assembly of bulk frameworks prevents full exploitation of the high surface area and connectivity offered by nanoscale fibres. As a result, the capacity for hydrogen bonding is reduced, thereby increasing the non-PCM mass fraction required for effective shape stabilisation. This study presents a novel, water-based processing approach utilising high aspect ratio cellulose nanofibrils (CNFs) extracted from the macroalgae Laminaria Hyperborea, characterised by a predominance of the α-cellulose crystalline allomorph [3]. By homogenising the CNFs with PEG1000 and subsequently lyophilising the mixture, a three-dimensional, nanoscale porous network is achieved, enabling strong hydrogen bonding between the cellulose hydroxyl groups and PCM molecules. This method eliminates the need for toxic solvents or additives and avoids the formation of macro-scale voids inherent in vacuum impregnation, thereby fully exploiting the nanofibrillar structure for improved retention and mechanical integrity. The critical role of cellulose source and crystalline structure is demonstrated in this study; α-cellulose provides superior structural properties compared to commonly used wood-derived cellulose[4] and enables exceptional PCM retention. Systematic investigation revealed that a high composite density with only 12.5% cellulose content reduces leakage after 100 cycles below 3%. Increasing the cellulose content to 15% under the same conditions resulted in complete leakage depletion. Differential scanning calorimetry confirmed that the composite retained 83% of its initial enthalpy after 100 cycles, while the latent heat was 77% of pure PEG due to the restricted mobility within the nanofibrillar matrix. Brunauer–Emmett–Teller analysis further established that decreasing pore size, a function of increased nanofibril content and density, correlates with a modest reduction in enthalpy, reflecting the balance between shape stability and storage capacity. By reducing the non-PCM mass fraction while maintaining outstanding thermal and mechanical performance, this approach advances the development of scalable, environmentally friendly, and high-performance PCM composites. The results demonstrate that the selection of cellulose source and processing method are decisive factors for next-generation, sustainable thermal energy storage materials.
| Item Type: | Book Section |
|---|---|
| Faculty \ School: | Faculty of Science Faculty of Science > School of Engineering, Mathematics and Physics |
| UEA Research Groups: | Faculty of Science > Research Groups > Sustainable Energy Faculty of Science > Research Groups > Fluids & Structures |
| Related URLs: | |
| Depositing User: | LivePure Connector |
| Date Deposited: | 10 Apr 2026 09:30 |
| Last Modified: | 10 Apr 2026 09:30 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/102745 |
| DOI: |
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