The development of multifunctional materials inspired by biological systems has gained
increasing attention due to their structural efficiency, adaptability, and sustainability. Among
these, hydrogels derived from natural polymers such as sodium alginate offer significant
potential for use in additive manufacturing, particularly in bioprinting and soft tissue
engineering. However, their printability and mechanical performance depend strongly on
effective chemical modification and photo-crosslinking behaviour.
This study focused on the chemical modification of sodium alginate to create a photocrosslinkable hydrogel precursor using methacrylate reagents suitable for direct light
processing (DLP). Three methacrylation routes, using methacrylic anhydride (MA), glycidyl
methacrylate (GMA), and 2-aminoethyl methacrylate (AEMA), were compared to evaluate
the degree of methacrylation (DOM), effect on hydrogel crosslinking density, and printing
performance.
The MA route was identified as the most practical and economical method, whereas the
AEMA route required costly carbodiimide coupling reagents, and the GMA route was
expected to exhibit inconsistent crosslinking. Rheological characterization further revealed
that higher DOM in MA-modified gels produced larger storage moduli (G′) and shorter linear
viscoelastic ranges, indicating increased crosslink density and brittleness.
Cure depth analysis was used to estimate exposure times for DLP, but the theoretical values
(0.43 s for AEMA-based and 0.44 s for MA-based resins at 0.05–0.5 mm slice thickness) were
impractically short. Printing trials confirmed that these estimates were inadequate, as they
did not account for the crosslinking degree required to achieve sufficient mechanical stability.
A trial-and-error optimization approach achieved limited success with an AEMA route (DOM
= 17%) resin and produced significant defects with lower DOM MA route (DOM = 7%)
formulations. Further optimization of printing parameters and resin formulation is necessary
to enable the fabrication of complex and mechanically robust DLP-printed structures.
| Date of Award | 22 Jan 2026 |
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| Original language | English |
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| Awarding Institution | - University Of Strathclyde
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| Sponsors | University of Strathclyde |
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| Supervisor | K H Aaron Lau (Supervisor) & James Windmill (Supervisor) |
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