We have a long-term research focus on the following aspects of biopolymers (e.g. starch, chitosan, cellulose, alginate, gelatin):
- Multilevel structures
- Molecular interactions (e.g. hydrogen bonding, ionic interaction)
- Dissolution and plasticisation
- Chemical and physical modification
- Innovative processing and manufacturing (reactive processes, ‘green’ processes, emerging techniques)
- Structural evolution during processing, modification, ageing and usage
- Blends, composites and nanocomposites
- Processing-structure-property relationships
Featured research findings
- The thermal transition of starch is largely influenced by the ratio of ionic liquid/water. Aqueous ionic liquid with a certain ionic liquid/water ratio leads to the most effective structural disorganisation and amorphisation of starch at significantly reduced temperature (even at room temperature) (read Carbohydr. Polym. 2013, 94, 520-530; Phys Chem Chem Phys 2015, 17, 13860-13871; ACS Sustainable Chem. Eng., 2017, 5 (5), 3737-3741). This also allows the effective plasticisation of starch in a highly concentrated state under “melt” processing (read ACS Sustainable Chem. Eng. 2017, 5 (6), 5457-5467).
- Starch, even high-amylose starch, can be fully dissolved by aqueous metal chloride salts (e.g. ZnCl2, CaCl2, MgCl2) at moderate temperature; starch nanoparticles forms resulting from this dissolution process (read Carbohydr. Polym. 2016, 136, 266-273; ACS Sustainable Chem. Eng. 2020, 8 (12), 4838-4847). Under “melt” processing, ZnCl2 solution has an excellent plasticisation effect on starch and in-situ formed starch-zinc complexes can enhance the mechanical properties of starch-based materials (read Carbohydr. Polym. 2019, 206, 528-538). Simply mixing CaCl2 solution with starch can lead to starch-based materials with ionic conductivity and strain-responsiveness (read ACS Sustainable Chem. Eng. 2020, 8 (51), 19117-19128).
- Under “melt” processing with limited solvents, chitosan-based materials and composites can be prepared cost-effectively (read Polymer 2013, 54 (14), 3654-3662). Prepared in this way, chitosan/silk peptide blends show extraordinary mechanical properties (A, below) (read ACS Sustainable Chem. Eng. 2019, 7 (2), 2792-2802) and chitosan/carboxymethyl cellulose blends have unexpected hydrolytic stability, better than that of each biopolymer component (B, below) (read Compos. Sci. Technol. 2020, 189, 108031), likely due to polyelectrolyte complexation.
Through our recent research into chitosan-based nanocomposites, we have:
- Identified factors determining nanofiller dispersion in biopolymers identified;
- Revealed mechanisms regarding nanofiller reinforcement effect on biopolymers;
- Uncovered the influence of material formulation (nanofiller, plasticiser, and biopolymer blending) on surface hydrophilicity;
- Elaborated competing interactions among biopolymer, nanofiller and plasticiser;
- Shown unexpected structures and properties of biopolymer composites (e.g. hydrolytic stability and high relative permittivity).
- Breaking Frontiers for advanced engineering of bespoke, functional Biopolymer Composite materials (FROBCO), EP/V002236/1, EPSRC Fellowship (Learn more)