Research and Application Directions of Nanocellulose-Based Hydrogels

Why Nanocellulose Is Well Suited for Hydrogel Construction

CNF has a high aspect ratio and a strong ability to form three-dimensional fibrillar networks. CNC features a rigid nanocrystalline structure and a readily functionalizable surface, while BC naturally forms a highly hydrated nanofibrous network. These three types of nanocellulose can all participate in hydrogel network formation through physical entanglement, hydrogen bonding, ionic interactions, or chemical crosslinking.

The role of nanocellulose extends far beyond simply “increasing the solids content.” In composite hydrogels, nanocellulose can serve as a reinforcing scaffold, rheological modifier, functional carrier, or multiscale network node, thereby improving the gel’s mechanical strength, shape retention, water uptake behavior, and dispersion of functional components.

Crosslinking Strategies Are Becoming Increasingly Diverse

Current research encompasses a wide range of crosslinking approaches, including physical crosslinking, ionic crosslinking, dynamic covalent bonding, free-radical polymerization, and double-network architectures. Carboxylated nanocellulose can form ionic interactions with multivalent ions or positively charged components. Double-bond-functionalized CNCs can participate in polymerization or crosslinking reactions, while dialdehyde-functionalized cellulose materials can react with amino-containing components, providing additional pathways for constructing tunable hydrogel networks.

Therefore, the key to selecting nanocellulose for hydrogel applications is not simply whether to choose CNC or CNF, but rather to first determine the specific role that nanocellulose is expected to play in the hydrogel system—whether as a reinforcing phase, thickening agent, crosslinking component, functional carrier, conductive scaffold, or water-retention component.

Emerging Hotspots Since 2025

Recent review studies indicate that nanocellulose-based hydrogels are continuing to expand into a range of applications, including water retention and controlled-release systems in agriculture, food packaging, removal of pollutants from water, sensing, and conductive hydrogels. In agriculture, research focuses on soil water retention and controlled fertilizer release. In environmental applications, key areas include adsorption, membrane separation, and catalytic supports. Conductive hydrogels, meanwhile, are being developed by integrating nanocellulose with conductive polymers, carbon-based materials, or two-dimensional materials for applications in flexible sensing and wearable devices.

A common feature across these emerging directions is that hydrogels are no longer viewed simply as “soft materials containing large amounts of water.” Instead, through deliberate network architecture design, they can integrate mechanical properties, mass transport, stimuli-responsive behavior, and functional loading within a single material platform.

Key Evaluation Metrics in Application Development

The key evaluation criteria for hydrogels vary significantly depending on the intended application. Structural materials place greater emphasis on compressive/tensile properties and cyclic stability. Adsorbent materials are evaluated primarily in terms of pore structure, functional groups, and adsorption capacity. Controlled-release systems focus on diffusion behavior and release profiles. Flexible electronics require appropriate electrical conductivity, strain responsiveness, and fatigue resistance. For bio-related applications, additional considerations include biocompatibility, sterilization, and applicable regulatory requirements.

Therefore, product development should work backward from the target application to determine the appropriate network architecture, rather than using “whether a gel is formed” as the sole criterion for success.

CelluBio Material Selection Strategy

When a pronounced fibrillar network and rheological support are required, CNF-based systems such as carboxylated CNF (C-CNF) can be considered as a priority. When nanoscale rigid reinforcement or surface functionalization is desired, CNC can be evaluated. For applications requiring participation in polymerization or crosslinking reactions, functionalized nanocelluloses containing double bonds, dialdehyde groups, or other reactive functional groups may be considered. When a naturally formed, hydrated nanofibrous network is required, bacterial cellulose (BC/BNC) is also an important material option.

Sources and Further Reading

• Lakhani, K.G. et al. Nanocellulose-hydrogel hybrids: A review on synthesis and applications in agriculture, food packaging and water remediation. International Journal of Biological Macromolecules, 2025, 309:143081.

• Zhang, M. et al. Functionalities and properties of conductive hydrogel with nanocellulose integration. Chemical Engineering Journal, 2025, 506:159872.

Note: This article is intended for technical exchange and discussion within the industry and is based on publicly available research and technological developments. The specific properties and performance of the materials may vary depending on raw materials, surface chemistry, dispersion state, formulation, and processing conditions. Actual applications should be validated through laboratory-scale testing. For applications involving food, medical, or other regulated fields, applicable regulations and compliance requirements for the end products must also be satisfied.