Microstructured Thermo-Responsive Double Network Granular Hydrogels

Thoma A, Whatmore R, et al.

Materials Advances

École Polytechnique Fédérale de Lausanne

RESEARCH SUMMARY

Introduces thermo-responsive double network granular hydrogels (TDNGHs) that combine fast actuation and load-bearing capabilities. These hydrogels consist of microporous PNIPAM microfragments connected via a secondary polymer network (PAM or PNIPAM). Porous fragments accelerate temperature-triggered deswelling threefold while maintaining mechanical integrity. Small micropores increased fracture work up to 18-fold without compromising Young’s modulus, while maintaining printability for complex shapes like bilayers and butterflies. Actuation in 70 °C water induced bending, lifting weights up to 85% of the hydrogel’s own mass, and motion of 3D-printed objects, demonstrating potential for soft robotic applications.

Tensile tests were conducted on dogbone PNIPAM samples using a CellScale UniVert mechanical tester with a 5 kN load cell at 60 °C. Samples were heated to 60 °C in a closed water-filled container, clamped, and stretched at 100 mm/min until failure. Stress–strain data were used to calculate Young’s modulus (strain range 5–15%) for hydrogels made from homogeneous or microporous fragments. Results showed that microporosity improved mechanical resilience without reducing modulus.

AUTHORS

Thoma A; Whatmore R; Amstad E.

PUBLICATION DETAILS

JOURNAL

Materials Advances

YEAR

2025

INSTITUTIONS

École Polytechnique Fédérale de Lausanne

COUNTRIES

Switzerland

INSTRUMENT USED

UniVert

TESTING METHODS

Hydrated and Temperature Controlled TestingTensile Testing

RESEARCH APPLICATIONS

3D Bioprinting & Bioink Materials TestingHydrogel Mechanical TestingMaterial Fatigue and DurabilityPolymers and Elastomers TestingSoft Robotics MaterialsStimuli Responsive Hydrogels Characterization

Related Publications:

Instrument Used:

Year:

Testing Method:

Research Application:

Country:

Hydrophilic Polydopamine (hPDA) Fueled Bioglue Enhances Tissue Adhesion and Promotes Healing of Avascular Meniscus Tears

Jani HR, Jeremias MA, et al.

Biomaterials

UniVert

Compression TestingShear TestingTensile Testing

Adhesives and Sealants TestingCartilage and Meniscus MechanicsHydrogel Mechanical TestingInjectable & Regenerative BiomaterialsScaffold Mechanical Testing

2026

Mycoelectronics: Bioprinted Living Fungal Bioelectronics for Artificial Sensation

Cai X, Ofori-Boateng S, et al.

Proceedings of the National Academy of Sciences (PNAS)

UniVert

Tensile Testing

Cell Laden HydrogelsHydrogel Mechanical TestingSoft Robotics MaterialsWearable Bioelectronics

2026

Machine Learning-Enabled Prediction of Spatiotemporal Strain Evolution in Stereolithography-Fabricated Architected Hydrogels

Sun H, Traczik S, et al.

ACS Applied Engineering Materials

UniVert

Digital Image Correlation (DIC)Hydrated and Temperature Controlled TestingTensile Testing

Hydrogel Mechanical TestingPolymers and Elastomers TestingSoft Robotics Materials

2026