Wide-Angle X-ray Diffraction of Cellulose Nanocrystal−Alginate Nanocomposite Fibers

In situ biomineralization reinforcing anisotropic nanocellulose scaffolds for guiding the differentiation of bone marrow-derived mesenchymal stem cells

Nanocellulose (NC) is a promising biopolymer for various biomedical applications owing to its biocompatibility and low toxicity. However, it faces challenges in tissue engineering (TE) applications due to the inconsistency of the microenvironment within the NC-based scaffolds with target tissues, including anisotropy microstructure and biomechanics. To address this challenge, a facile swelling-induced nanofiber alignment and a novel in situ biomineralization reinforcement strategies were developed for the preparation of NC-based scaffolds with tunable anisotropic structure and mechanical strength for guiding the differentiation of bone marrow-derived mesenchymal stem cells for potential TE application. The bacterial cellulose (BC) and cellulose nanofibrils (CNFs) based scaffolds with tunable swelling anisotropic index in the range of 10-100 could be prepared by controlling the swelling medium. The in situ biomineralization efficiently reinforced the scaffolds with 2-4 times and 10-20 times modulus increasement for BC and CNFs, respectively. The scaffolds with higher mechanical strength were superior in supporting cell growth and proliferation, suggesting the potential application in TE application. This work demonstrated the feasibility of the proposed strategy in the preparation of scaffolds with mechanical anisotropy to induce cells-directed differentiation for TE applications.

Diverse Approaches in Wet-Spun Alginate Filament Production from the Textile Industry Perspective: From Process Optimization to Composite Filament Production

Alginate, categorized as a natural-based biodegradable polymer, stands out for its inherently exclusive properties. Although this unique polymer is widely processed using film, coating, and membrane technologies for different usage areas, textile applications are still limited. This study aims to compile promising approaches that will pave the way for the use of wet-spun alginate filaments in textile applications. In this regard, this study provides information about the molecular structure of alginate, the gel formation mechanism, and cross-linking using different techniques. Our literature review categorizes parameters affecting the mechanical properties of wet-spun alginate filaments, such as the effect of ion source and spinning dope concentration, needle diameter, temperature, and coagulants. Following this, a detailed and comprehensive literature review of the various approaches, such as use of additives, preparation of blended filaments, and grafted nanocrystal addition, developed by researchers to produce composite alginate filaments is presented. Additionally, studies concerning the use of different cations in the coagulation phase are reported. Moreover, studies about the functionalism of wet-spun alginate filaments have been offered.

Cellulose Nanocrystal (CNC) Gels: A Review

The aim of this article is to review the research conducted in the field of aqueous and polymer composites cellulose nanocrystal (CNC) gels. The experimental techniques employed to characterize the rheological behavior of these materials will be summarized, and the main advantages of using CNC gels will also be addressed in this review. In addition, research devoted to the use of numerical simulation methodologies to describe the production of CNC-based materials, e.g., in 3D printing, is also discussed. Finally, this paper also discusses the application of CNC gels along with additives such as cross-linking agents, which can represent an enormous opportunity to develop improved materials for manufacturing processes.

Different amount of carboxyl-aldehyde fractionated nanofibril cellulose and main characteristics of chitosan, gelatin, alginate added composites

In this research, two different types of nanofibrillated celluloses (NFCs) having different amounts of aldehyde and carboxyl groups were mixed with chitosan (CH), gelatin (GL), and alginate (AL) with different mixing ratios to produce biocomposite aerogels. There was no related study in the literature about producing aerogels with the addition of NC and mentioning biopolymers in addition to the effect of carboxyl and aldehyde fraction of the main matrix NC on composite properties. For this purpose, the main aim of this study was to investigate how carboxyl and aldehyde groups affect the basic characteristics of NFC-biopolymer based materials addition to efficiency of biopolymer amount in main matrix. Even after preparing homogenous NC-biopolymer compositions at 1 % concentration with varied proportions (75 %-25 %, 50 %-50 %, 25 %-75 %, 100 %), aerogels were still made using the fundamentally easy lyophilization procedure. Porosity values for NC-Chitosan (NC/CH) based aerogels range from 97.85 to 99.84 %, whereas those made from NC-Gelatin (NC/GL) and NC-Alginate (NC-AL) have values of 99.2-99.8 % and 98.47 to 99.7 %, respectively. In addition, densities were determined in the range of 0.01 g/cm³ for both NC-CH and NC-GL composites, but higher values were obtained in ranged between 0.01 and 0.03 g/cm³ for NC-AL samples. The crystallinity index values showed a decreasing trend with the addition of biopolymers into NC composition. SEM images showed that all materials have a porous micro structure with different size pores and homogenous surface topography. As a result of the specified tests, these materials can be used in many different industrial applications, such as dust collectors, liquid adsorbers, specific material for packaging and medical materials.

Effect of the Interactions between Oppositely Charged Cellulose Nanocrystals (CNCs) and Chitin Nanocrystals (ChNCs) on the Enhanced Stability of Soybean Oil-in-Water Emulsions

Chitin nanocrystals (ChNCs) and cellulose nanocrystals (CNCs) have been recently used to stabilize emulsions; however, they generally require significant amounts of salt, limiting their applicability in food products. In this study, we developed nanoconjugates by mixing positively charged ChNCs and negatively charged CNCs at various ChNC:CNC mass ratios (2:1, 1:1, and 1:2), and utilized them in stabilizing soybean oil-water Pickering emulsions with minimal use of NaCl salt (20 mM) and nanoparticle (NP) concentrations below 1 wt%. The nanoconjugates stabilized the emulsions better than individual CNC or ChNC in terms of a reduced drop growth and less creaming. Oppositely charged CNC and ChNC neutralized each other when their mass ratio was 1:1, leading to significant flocculation in the absence of salt at pH 6. Raman spectroscopy provided evidence for electrostatic interactions between the ChNCs and CNCs, and generated maps suggesting an assembly of ChNC bundles of micron-scale lengths intercalated by similar-size areas predominantly composed of CNC. The previous measurements, in combination with contact angles on nanoparticle films, suggested that the conjugates preferentially exposed the hydrophobic crystalline planes of CNCs and ChNCs at a 1:1 mass ratio, which was also the best ratio at stabilizing soybean oil-water Pickering emulsions.

Understanding the Mechanical Reinforcement of Metal-Organic Framework-Polymer Composites: The Effect of Aspect Ratio

The aspect ratio (AR) of filler particles is one of the most critical determinants for the mechanical properties of particle-reinforced polymer composites. However, it has been challenging to solely study the effect of particle AR due to the difficulties of controlling AR without altering the physical and chemical properties of the particle. Herein, we synthesized PCN-222, a zirconium-based porphyrinic metal-organic framework (MOF) with preferential longitudinal growth as a series of particles with ARs increasing from 3.4 to 54. The synthetic MOF conditions allowed for the chemical properties of the particles to remain constant over the series. The particles were employed as reinforcers for poly(methyl methacrylate) (PMMA). MOF-polymer composite films were fabricated using doctor-blading techniques, which facilitated particle dispersion and alignment in the PMMA matrix, as revealed by optical microscopy and wide-angle X-ray diffraction. Mechanical measurements showed that both elastic and dynamic moduli increased with particle AR and particle concentrations but started to decrease as particle loading increased beyond 0.5 wt % (1.12 vol %). The data obtained at low particle loadings were fitted well with the Halpin-Tsai model. In contrast, the percolation model and the Cox model were unable to adequately fit the data, indicating the mechanical reinforcement in our system mainly originated from efficient load transfer between particles and the matrix in the particle orienting direction. Finally, we showed that the thermal stability of composite films increased with the addition of MOF particles because of the high thermal degradation temperature and restricted polymer chain mobility.

Methylcellulose-Cellulose Nanocrystal Composites for Optomechanically Tunable Hydrogels and Fibers

Chemical modification of cellulose offers routes for structurally and functionally diverse biopolymer derivatives for numerous industrial applications. Among cellulose derivatives, cellulose ethers have found extensive use, such as emulsifiers, in food industries and biotechnology. Methylcellulose, one of the simplest cellulose derivatives, has been utilized for biomedical, construction materials and cell culture applications. Its improved water solubility, thermoresponsive gelation, and the ability to act as a matrix for various dopants also offer routes for cellulose-based functional materials. There has been a renewed interest in understanding the structural, mechanical, and optical properties of methylcellulose and its composites. This review focuses on the recent development in optically and mechanically tunable hydrogels derived from methylcellulose and methylcellulose-cellulose nanocrystal composites. We further discuss the application of the gels for preparing highly ductile and strong fibers. Finally, the emerging application of methylcellulose-based fibers as optical fibers and their application potentials are discussed.

Anisotropic bacterial cellulose hydrogels with tunable high mechanical performances, non-swelling and bionic nanofluidic ion transmission behavior

Water-rich hydrogels with tissue-like softness, especially ion conductive hydrogels with ion signal transfer systems similar to biological areas, are promising soft electrode materials, while too poor or unstable mechanical properties that come from uncontrollable swelling and biocompatibility issues caused by introducing high concentration ions are serious obstacles in practical applications. Herein, a simple method for fabricating strong, stable, ion-conductive, anisotropic bacterial cellulose hydrogels (ABCHs) is first reported. Relying on nanofibers with high aspect ratio in bacterial cellulose (BC), a tailor-made nanofiber-network-reinforced structure is constructed by controlled dissolution, followed by aligning them well via a simple fossilizing process under stretching. Therefore, tunable high mechanical performances can be achieved and the maximum tensile strength can reach 14.3 MPa with 70% water content. It is worth noting that ABCHs will not swell in water for 30 days and maintain 93% tensile strength. Most importantly, the unique nanofluid behaviors from nanochannels in nanofibers allow effective ion transport in ABCHs relying only on low concentrations of ions in body fluids (<300 mM), avoiding sacrificing biocompatibility to achieve useful conductivity. This facile strategy might be very scalable in fabricating high-strength, non-swelling, bio-ion conductive cellulose hydrogels for application in next-generation bio-interfacing and flexible implantable devices.

Field-Assisted Alignment of Cellulose Nanofibrils in a Continuous Flow-Focusing System

The continuous production of macroscale filaments of 17 μm in diameter comprising aligned TEMPO-oxidized cellulose nanofibrils (CNFs) is conducted using a field-assisted flow-focusing process. The effect of an AC external field on the material's structure becomes significant at a certain voltage, beyond which augmentations of the CNF orientation factor up to 16% are obtained. Results indicate that the electric field significantly contributes to improve the CNF ordering in the bulk, while the CNF alignment on the filament surface is only slightly affected by the applied voltage. X-ray diffraction shows that CNFs are densely packed anisotropically in the plane parallel to the filament axis without any preferential out of plane orientation. The improved nanoscale ordering combined with the tight CNF packing yields impressive enhancements in mechanical properties, with stiffness up to 25 GPa and more than 63% (up to 260 MPa), 46% (up to 2.8%), and 120% (up to 4.7 kJ/m³) increase in tensile strength, strain-to-failure, and toughness, respectively. This study demonstrates for the first time the control over the structural ordering of anisotropic nanoparticles in a dynamic system using an electric field, which can have important implications for the development of sustainable alternatives to synthetic textiles.

Checkered Films of Multiaxis Oriented Nanocelluloses by Liquid-Phase Three-Dimensional Patterning

It is essential to build multiaxis oriented nanocellulose films in the plane for developing thermal or optical management films. However, using conventional orientation techniques, it is difficult to align nanocelluloses in multiple directions within the plane of single films rather than in the thickness direction like the chiral nematic structure. In this study, we developed the liquid-phase three-dimensional (3D) patterning technique by combining wet spinning and 3D printing. Using this technique, we produced a checkered film with multiaxis oriented nanocelluloses. This film showed similar retardation levels, but with orthogonal molecular axis orientations in each checkered domain as programmed. The thermal transport was enhanced in the domain with the oriented pattern parallel to the heat flow. This liquid-phase 3D patterning technique could pave the way for bottom-up design of differently aligned nanocellulose films to develop sophisticated optical and thermal materials.

Bioinspired hierarchical helical nanocomposite macrofibers based on bacterial cellulose nanofibers

Bio-sourced nanocellulosic materials are promising candidates for spinning high-performance sustainable macrofibers for advanced applications. Various strategies have been pursued to gain nanocellulose-based macrofibers with improved strength. However, nearly all of them have been achieved at the expense of their elongation and toughness. Inspired by the widely existed hierarchical helical and nanocomposite structural features in biosynthesized fibers exhibiting exceptional combinations of strength and toughness, we report a design strategy to make nanocellulose-based macrofibers with similar characteristics. By combining a facile wet-spinning process with a subsequent multiple wet-twisting procedure, we successfully obtain biomimetic hierarchical helical nanocomposite macrofibers based on bacterial cellulose nanofibers, realizing impressive improvement in their tensile strength, elongation and toughness simultaneously. The achievement certifies the validity of the bioinspired hierarchical helical and nanocomposite structural design proposed here. This bioinspired design strategy provides a potential platform for further optimizing or creating many more strong and tough nanocomposite fiber materials for diverse applications.

Liquid-Behaviors-Assisted Fabrication of Multidimensional Birefringent Materials from Dynamic Hybrid Hydrogels

Liquid-solid transition is a widely used strategy to shape polymeric materials and encode their microstructures. However, it is still challenging to fully exploit liquid behaviors of material precursors. In particular, the dynamic and static liquid behaviors naturally conflict with each other, which makes it difficult to integrate their advantages in the same materials. Here, by utilizing a shear-thinning phenomenon in the dynamic hybrid hydrogels, we achieve a hydrodynamic alignment of cellulose nanocrystals (CNC) and preserve it in the relaxed hydrogel networks due to the much faster relaxation of polymer networks (within 500 s) than CNC after the unloading of external force. During the following drying process, the surface tension of hydrogels further enhances the orientation index of CNC up to 0.872 in confined geometry, and these anisotropic microstructures demonstrate highly tunable birefringence (up to 0.004 14). Due to the presence of the boundaries of dynamic hydrogels, diverse xerogels including fibers, films, and even complex three-dimensional structures with variable anisotropic microstructures can be fabricated without any external molds.

Photonic-structured fibers assembled from cellulose nanocrystals with tunable polarized selective reflection

Fibers with self-assembled photonic structures are of special interest due to their unique photonic properties and potential applications in the smart textile industry. Inspired by nature, the photonic-structured fibers were fabricated through the self-assembly of chiral nematic cellulose nanocrystals (CNCs) and the fibers showed tunably brilliant and selectively reflected colors under crossed-polarization. A simple wet-spinning method was applied to prepare composite fibers of the mixed CNC matrix and polyvinyl alcohol (PVA) additions. During the processing, a cholesteric CNC phase formed photonic fibers through a self-assembly process. The selective color reflection of the composite fibers in the polarized condition showed a typical red-shift tendency with an increase in the PVA content, which was attributed to the increased helical pitch of the CNC. Furthermore, the polarized angle could also alter the reflected colors. Owing to their excellent selective reflection properties under the polarized condition, CNC-based photonic fibers are promising as the next-generation of smart fibers, applied in the fields of specific display and sensing.

Dynamics of Cellulose Nanocrystal Alignment during 3D Printing

The alignment of anisotropic particles during ink deposition directly affects the microstructure and properties of materials manufactured by extrusion-based 3D printing. Although particle alignment in diluted suspensions is well described by analytical and numerical models, the dynamics of particle orientation in the highly concentrated inks typically used for printing via direct ink writing (DIW) remains poorly understood. Using cellulose nanocrystals (CNCs) as model building blocks of increasing technological relevance, we study the dynamics of particle alignment under the shear stresses applied to concentrated inks during DIW. With the help of in situ polarization rheology, we find that the time period needed for particle alignment scales inversely with the applied shear rate and directly with the particle concentration. Such dependences can be quantitatively described by a simple scaling relation and qualitatively interpreted in terms of steric and hydrodynamic interactions between particles at high shear rates and particle concentrations. Our understanding of the alignment dynamics is then utilized to estimate the effect of shear stresses on the orientation of particles during the printing process. Finally, proof-of-concept experiments show that the combination of shear and extensional flow in 3D printing nozzles of different geometries provides an effective means to tune the orientation of CNCs from fully aligned to core-shell architectures. These findings offer powerful quantitative guidelines for the digital manufacturing of composite materials with programmed particle orientations and properties.

Inverse Thermoreversible Mechanical Stiffening and Birefringence in a Methylcellulose/Cellulose Nanocrystal Hydrogel

We show that composite hydrogels comprising methyl cellulose (MC) and cellulose nanocrystal (CNC) colloidal rods display a reversible and enhanced rheological storage modulus and optical birefringence upon heating, i.e., inverse thermoreversibility. Dynamic rheology, quantitative polarized optical microscopy, isothermal titration calorimetry (ITC), circular dichroism (CD), and scanning and transmission electron microscopy (SEM and TEM) were used for characterization. The concentration of CNCs in aqueous media was varied up to 3.5 wt % (i.e, keeping the concentration below the critical aq concentration) while maintaining the MC aq concentration at 1.0 wt %. At 20 °C, MC/CNC underwent gelation upon passing the CNC concentration of 1.5 wt %. At this point, the storage modulus ( G') reached a plateau, and the birefringence underwent a stepwise increase, thus suggesting a percolative phenomenon. The storage modulus ( G') of the composite gels was an order of magnitude higher at 60 °C compared to that at 20 °C. ITC results suggested that, at 60 °C, the CNC rods were entropically driven to interact with MC chains, which according to recent studies collapse at this temperature into ring-like, colloidal-scale persistent fibrils with hollow cross-sections. Consequently, the tendency of the MC to form more persistent aggregates promotes the interactions between the CNC chiral aggregates towards enhanced storage modulus and birefringence. At room temperature, ITC shows enthalpic binding between CNCs and MC with the latter comprising aqueous, molecularly dispersed polymer chains that lead to looser and less birefringent material. TEM, SEM, and CD indicate CNC chiral fragments within a MC/CNC composite gel. Thus, MC/CNC hybrid networks offer materials with tunable rheological properties and access to liquid crystalline properties at low CNC concentrations.

Macrofibers with High Mechanical Performance Based on Aligned Bacterial Cellulose Nanofibers

Bacterial cellulose (BC) nanofibers represent an emerging class of highly crystalline bionanofibers with high intrinsic mechanical properties. The remarkable nanofibers with oriented structure and strong interfibrillar interactions can realize high-performance materials. In this study, we demonstrated that macrofibers based on aligned BC nanofibers could be prepared by wet spinning and drawing procedures. The relationship between process conditions, structure, and mechanical properties of macrofibers were investigated. The obtained macrofibers exhibited Young's modulus of 16.4 GPa and tensile strength of 248.6 MPa under the optimum process conditions, in which nanofibers displayed a high degree of alignment. Furthermore, we enhanced the interfacial interactions between nanofibers and obtained better mechanical performance by multivalent ion cross-linking. After exchanging the monovalent Na⁺ by Fe³⁺, the dried macrofiber reached Young's modulus of 22.9 GPa and tensile strength of 357.5 MPa. Particularly, the resulting macrofibers still maintained good mechanical properties with Young's modulus of 15.9 GPa and tensile strength of 262.2 MPa in the wet condition. This research provided a good method to fabricate macrofibers from BC nanofibers with good properties by continuous wet-spinning process. These macrofibers can be easily functionalized and have promising potential applications in smart textiles, biosensor, and structural reinforcement.

Single-stranded structure of alginate and its conformation evolvement after an interaction with calcium ions as revealed by electron microscopy

Calcium alginate shows a stable tangling conformation with an enlarged egg-box assembly.

Gel Spinning of Polyacrylonitrile/Cellulose Nanocrystal Composite Fibers

Polyacrylonitrile (PAN)/cellulose nanocrytal (CNC) fibers containing 0, 1, 5, and 10 wt % CNCs have been successfully produced by gel spinning. The rheological properties of solutions were investigated and the results showed that the complex viscosity and storage modulus of solutions were significantly affected by the presence of CNCs in the solution. Structure, morphology, mechanical properties and dynamic mechanical properties of these fibers have been investigated. Tensile modulus and strength increased from 14.5 to 19.6 GPa and from 624 to 709 MPa, respectively, as CNC loading increased from 0 to 10 wt %. Wide-angle X-ray diffraction results showed better PAN chain alignment and higher PAN crystallinity with the incorporation of CNCs.

Aligned bioinspired cellulose nanocrystal-based nanocomposites with synergetic mechanical properties and improved hygromechanical performance

Natural high-performance materials inspire the pursuit of ordered hard/soft nanocomposite structures at high fractions of reinforcements and with balanced supramolecular interactions. Such biomimetic design principles remain difficult to realize for bulk nanocomposites. Herein, we establish an effective drawing procedure that induces a high orientation of crystalline cellulose nanocrystals (CNCs) in a matrix of carboxymethylcellulose (CMC) at high level of reinforcements (50 vol %). We show such alignment in rather thick bulk films and report synergetic improvement with a simultaneous increase of stiffness, strength, and work-to-fracture as a function of the degree of alignment. Scanning electron microscopy and two-dimensional X-ray diffraction quantify the alignment of the cylindrical nanoparticles and link it to the extent of drawing and improvements in mechanical properties. We further show that the decline in mechanical properties of such waterborne all biobased nanocomposites at high relative humidity can be balanced using supramolecular modulation of the ionic interactions by exchanging the monovalent Na(+) counterion, present in CMC and CNC with di- or trivalent Cu(2+) and Fe(3+). This contribution demonstrates the importance of aligning one-dimensional reinforcements to achieve synergetic improvement in mechanical properties in sustainable bioinspired nanocomposites and suggests pathways to prepare water-stable materials based on a waterborne processing route.

Effects of crystal orientation on cellulose nanocrystals-cellulose acetate nanocomposite fibers prepared by dry spinning

This work presents the development of dry spun cellulose acetate (CA) fibers using cellulose nanocrystals (CNCs) as reinforcements. Increasing amounts of CNCs were dispersed into CA fibers in efforts to improve the tensile strength and elastic modulus of the fiber. A systematic characterization of dispersion of CNCs in the polymer fiber and their effect on the nanocomposites' mechanical properties is described. The birefringence, thermal properties, and degree of CNC orientation of the fibers are discussed. 2D X-ray diffraction was used to quantify the degree of CNC alignment within the fibers. It is shown that the CNC alignment directly correlates to the mechanical properties of the composite. Maximum improvements of 137% in tensile strength and 637% in elastic modulus were achieved. Empirical micromechanical models Halpin-Tsai equation and an orientation modified Cox model were used to predict the fiber performance and compared with experimental results.

TEMPO-oxidized nanocellulose participating as crosslinking aid for alginate-based sponges

Crosslinked polysaccharide sponges have been prepared by freeze-drying of amorphous alginate-oxidized nanocellulose in the presence of a Ca(2+) ionic crosslinking agent. The new carboxyl groups on the surface of nanocellulose induced by the chemical oxidization provided the possibility of participating in the construction of an alginate-based sponge's structure and played a fundamental role in the structural and mechanical stability of ensuing sponges. Furthermore, enhanced mechanical strength induced by oxidized cellulose nanocrystals and the formation of a semi-interpenetrating polymer network from oxidized microfibrillated cellulose were reported. Together with the facile and ionic crosslinking process, the ultrahigh porosity, promising water absorption and retention, as well as the improved compression strength of the crosslinked sponges should significantly extend the use of this soft material in diverse practical applications.

Preparation, properties and applications of polysaccharide nanocrystals in advanced functional nanomaterials: a review

Intensive exploration and research in the past few decades on polysaccharide nanocrystals, the highly crystalline nanoscale materials derived from natural resources, mainly focused originally on their use as a reinforcing nanophase in nanocomposites. However, these investigations have led to the emergence of more diverse potential applications exploiting the functionality of these nanomaterials. Based on the construction strategies of functional nanomaterials, this article critically and comprehensively reviews the emerging polysaccharide nanocrystal-based functional nanomaterials with special applications, such as biomedical materials, biomimetic optical nanomaterials, bio-inspired mechanically adaptive nanomaterials, permselective nanostructured membranes, template for synthesizing inorganic nanoparticles, polymer electrolytes, emulsion nano-stabilizer and decontamination of organic pollutants. We focus on the preparation, unique properties and performances of the different polysaccharide nanocrystal materials. At the same time, the advantages, physicochemical properties and chemical modifications of polysaccharide nanocrystals are also comparatively discussed in view of materials development. Finally, the perspective and current challenges of polysaccharide nanocrystals in future functional nanomaterials are outlined.

Reorientation of cellulose nanowhiskers in agarose hydrogels under tensile loading

Agarose hydrogels filled with cellulose nanowhiskers were strained in uniaxial stretching under different humidity conditions. The orientation of the cellulose whiskers was examined before and after testing with an X-ray laboratory source and monitored in situ during loading by synchrotron X-ray diffraction. The aim of this approach was to determine the process parameters for reorienting the cellulose nanowhiskers toward a preferential direction. Results show that a controlled drying of the hydrogel is essential to establish interactions between the matrix and the cellulose nanowhiskers which allow for a stress transfer during stretching and thereby promote their alignment. Rewetting of the sample after reorientation of the cellulose nanowhiskers circumvents a critical increase of stress. This improves the extensibility of the hydrogel and is accompanied by a further moderate alignment of the cellulose nanowhiskers. Following this protocol, cellulose nanowhiskers with an initial random distribution can be reoriented toward a preferential direction, creating anisotropic nanocomposites.