Hybrid CNCs/PNIPAAm Thermoresponsive Hydrogels Showing Enhanced Mechanical Strength and Biocompatibility

Gautam B, Veenbrink VA, et al.

Journal of Polymer Science

Eindhoven University of Technology

RESEARCH SUMMARY

This study reports the synthesis of hybrid thermoresponsive hydrogels based on poly(N-isopropylacrylamide) (PNIPAAm) reinforced with low concentrations ( 99 % U-2 OS viability). Incorporation of CNCs increased the storage modulus up to 20× compared with pure PNIPAAm (6 kPa vs 0.3 kPa) and improved compression resistance sixfold. The material retained transparency, tunable stiffness, and surface wettability, enabling use as coatings or tissue-engineering scaffolds. This hybrid design provides an easily scalable route toward biocompatible smart hydrogels for wound dressings, medical adhesives, and responsive biomedical devices.

Compression tests were conducted using a CellScale MicroTester on pre-wetted hydrogel cubes (≈ 1 cm³) at room temperature. A circular tungsten microbeam (length 63 mm, diameter 0.406 mm) applied 1 % s⁻¹ compressive strain up to 25 % deformation. Force–displacement data (14 points per run) were processed to extract mechanical stiffness. Hybrid hydrogels with 0.74 wt % CNCs required ≈ 5.6 mN to reach 25 % strain—six times higher than pure PNIPAAm (0.9 mN)—demonstrating that CNC reinforcement provides a multifunctional cross-linking effect and superior stiffness retention under cyclic loading.

AUTHORS

Bhaskarchand Gautam, Victor A. Veenbrink, Caterina Rugina, Mats Sturm, Victor Nastaseanu, Tara Eijsbouts, Marcel Kiljański, A. Catarina C. Esteves.

PUBLICATION DETAILS

JOURNAL

Journal of Polymer Science

YEAR

2025

INSTITUTIONS

Eindhoven University of Technology

COUNTRIES

Netherlands

INSTRUMENT USED

MicroTester

TESTING METHODS

Compression TestingViscoelastic & Time-Dependent Testing

RESEARCH APPLICATIONS

Hydrogel Mechanical TestingInjectable & Regenerative BiomaterialsPolymers and Elastomers TestingStimuli Responsive Hydrogels Characterization

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