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ABSTRACT Formation of alginate‐based interpenetrating networks and addition of nanoparticles into these gels are widely used strategies to enhance the mechanical properties of alginate gels used for delivery and biomedical applications. Our previous work demonstrated that alginate‐clay nanocomposite hydrogels containing poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) copolymers exhibited significant enhancement of elasticity and temperature‐dependent rheology. However, the behavior of PEO–PPO–PEO copolymers within an alginate network remains unclear. In this study, we use small‐angle neutron scattering (SANS) to investigate the interactions between the alginate network and PEO–PPO–PEO triblock chains. Our fitting results revealed that the triblock chains can form micelles integrated into the alginate gel “egg box” structure at higher temperatures. The presence of the alginate network influences the formation of PEO–PPO–PEO micelles in our gels, leading to elongated ellipsoidal micelles rather than spherical micelles. Interestingly, as the temperature increased, these micelles did not expand in all three dimensions, as observed for pure PEO–PPO–PEO solutions. Rather, the total size increased only in one direction while remaining the same in the other two directions, suggesting that the alginate networks restrict the growth of micelles. Furthermore, we did not observe the distinct higher‐order peaks that are typical of cubic PEO–PPO–PEO hydrogels; rather, relatively weak secondary peaks were observed. These results demonstrate that the presence of the alginate network significantly influences micelle formation and assembly in composite hydrogel systems.
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Printable homocomposite hydrogels with synergistically reinforced molecular-colloidal networks
Abstract The design of hydrogels where multiple interpenetrating networks enable enhanced mechanical properties can broaden their field of application in biomedical materials, 3D printing, and soft robotics. We report a class of self-reinforced homocomposite hydrogels (HHGs) comprised of interpenetrating networks of multiscale hierarchy. A molecular alginate gel is reinforced by a colloidal network of hierarchically branched alginate soft dendritic colloids (SDCs). The reinforcement of the molecular gel with the nanofibrillar SDC network of the same biopolymer results in a remarkable increase of the HHG’s mechanical properties. The viscoelastic HHGs show >3× larger storage modulus and >4× larger Young’s modulus than either constitutive network at the same concentration. Such synergistically enforced colloidal-molecular HHGs open up numerous opportunities for formulation of biocompatible gels with robust structure-property relationships. Balance of the ratio of their precursors facilitates precise control of the yield stress and rate of self-reinforcement, enabling efficient extrusion 3D printing of HHGs.
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- Award ID(s):
- 1825476
- PAR ID:
- 10228262
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 12
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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