Bulk Material Properties Research Articles

Tantalum as a Novel Biomaterial for Bone Implant: A Literature Review

Titanium (Ti) has been used in metallic implants since the 1950s due to various biocompatible and mechanical properties. However, due to its high Young’s modulus, it has been modified over the years in order to produce a better biomaterial. Tantalum (Ta) has recently emerged as a new potential biomaterial for bone and dental implants. It has been reported to have better corrosion resistance and osteo-regenerative properties as compared to Ti alloys which are most widely used in the bone-implant industry. Currently, Tantalum cannot be widely used yet due to its limited availability, high melting point, and high-cost production. This review paper discusses various manufacturing methods of Tantalum alloys, including conventional and additive manufacturing and also discusses their drawbacks and shortcomings. Recent research includes surface modification of various metals using Tantalum coatings in order to combine bulk material properties of different materials and the porous surface properties of Tantalum. Design modification also plays a crucial role in controlling bulk properties. The porous design does provide a lower density, wider surface area, and more immense specific strength. In addition to improved mechanical properties, a porous design could also escalate the material's biological and permeability properties. With current advancement in additive manufacturing technology, difficulties in processing Tantalum could be resolved. Therefore, Tantalum should be considered as a serious candidate material for future bone and dental implants.

Additive Manufactured Scaffolds for Bone Tissue Engineering: Physical Characterization of Thermoplastic Composites with Functional Fillers.

Thermoplastic polymer–filler composites are excellent materials for bone tissue engineering (TE) scaffolds, combining the functionality of fillers with suitable load-bearing ability, biodegradability, and additive manufacturing (AM) compatibility of the polymer. Two key determinants of their utility are their rheological behavior in the molten state, determining AM processability and their mechanical load-bearing properties. We report here the characterization of both these physical properties for four bone TE relevant composite formulations with poly(ethylene oxide terephthalate)/poly(butylene terephthalate (PEOT/PBT) as a base polymer, which is often used to fabricate TE scaffolds. The fillers used were reduced graphene oxide (rGO), hydroxyapatite (HA), gentamicin intercalated in zirconium phosphate (ZrP-GTM) and ciprofloxacin intercalated in MgAl layered double hydroxide (MgAl-CFX). The rheological assessment showed that generally the viscous behavior dominated the elastic behavior (G″ > G′) for the studied composites, at empirically determined extrusion temperatures. Coupled rheological–thermal characterization of ZrP-GTM and HA composites showed that the fillers increased the solidification temperatures of the polymer melts during cooling. Both these findings have implications for the required extrusion temperatures and bonding between layers. Mechanical tests showed that the fillers generally not only made the polymer stiffer but more brittle in proportion to the filler fractions. Furthermore, the elastic moduli of scaffolds did not directly correlate with the corresponding bulk material properties, implying composite-specific AM processing effects on the mechanical properties. Finally, we show computational models to predict multimaterial scaffold elastic moduli using measured single material scaffold and bulk moduli. The reported characterizations are essential for assessing the AM processability and ultimately the suitability of the manufactured scaffolds for the envisioned bone regeneration application.

The Surface of (16) Psyche from Thermal Emission and Polarization Mapping

Abstract The asteroid (16) Psyche is the largest of the M-type asteroids, which have been hypothesized to be the cores of disrupted planetesimals and the parent bodies of the iron meteorites. While recent evidence has collected against a pure metal composition for Psyche, its spectrum and radar properties remain anomalous. We observed (16) Psyche in thermal emission with the Atacama Large Millimeter/submillimeter Array at a resolution of 30 km over two-thirds of its rotation. The diurnal temperature variations are at the ∼10 K level over most of the surface and are best fit by a smooth surface with a thermal inertia of 280 ± 100 J m−2 K−1 s−1/2. We measure a millimeter emissivity of 0.61 ± 0.02, which we interpret via a model that treats the surface as a porous mixture of silicates and metals, where the latter may take the form of iron sulfides/oxides or, alternatively, conducting metallic inclusions. The emissivity indicates a metal content of no less than 20% and potentially much higher, but the polarized emission that should be present for a surface with ≥20% metal content is almost completely absent. This requires a highly scattering surface, which may be due to the presence of reflective metallic inclusions. If such is the case, a consequence is that metal-rich asteroids may produce less polarized emission than metal-poor asteroids, exactly the opposite prediction from standard theory, arising from the dominance of scattering over the bulk material properties.

Linking grain boundary structure and composition to microstructure in commercial‐grade‐doped specialty Aluminas

AbstractThe design of commercial‐grade specialty alumina for improved behavior relies on better understanding the complex interplay between high concentrations of intentional dopants and unintentional impurities, which are unavoidably introduced during industrial‐scale processing. In particular, dopants and impurities govern grain boundary structure/composition, grain growth, and bulk material properties. While the effects of single dopants in ultra‐high‐purity ceramics are well understood, the same concepts have not been adequately extended to commercial materials containing numerous impurities, especially when utilizing the latest atomic‐resolution characterization techniques to evaluate grain boundary structure and composition. Therefore, this work investigated the effects of varying co‐doping levels of MgO, CaO, and SiO2 on grain boundary structure and composition in commercial‐grade alumina by applying aberration‐corrected scanning transmission electron microscopy. First, it was observed that grain growth behavior, specifically grain morphology, in doped specialty aluminas was anomalous to ultra‐high‐purity alumina; in the composition range that was investigated in this study, Ca‐doped specialty alumina exhibited equiaxed grains, whereas Si‐doped specialty alumina exhibited elongated grains. Afterward, it was determined that elemental ratios of bulk doping concentrations differed from grain boundary compositions. Grain boundary compositions, as well as grain boundary structure, were therefore determined to be the dominant metrics to predict grain growth behavior. Overall, co‐doping effects on grain boundary structure and composition are the key parameters to consider to control commercial‐grade ceramics and improve material reliability.

3D-Printed Architected Materials Inspired by Cubic Bravais Lattices.

Learning from Nature and leveraging 3D printing, mechanical testing, and numerical modeling, this study aims to provide a deeper understanding of the structure-property relationship of crystal-lattice-inspired materials, starting from the study of single unit cells inspired by the cubic Bravais crystal lattices. In particular, here we study the simple cubic (SC), body-centered cubic (BCC), and face-centered cubic (FCC) lattices. Mechanical testing of 3D-printed structures is used to investigate the influence of different printing parameters. Numerical models, validated based on experimental testing carried out on single unit cells and embedding manufacturing-induced defects, are used to derive the scaling laws for each studied topology, thus providing guidelines for materials selection and design, and the basis for future homogenization and optimization studies. We observe no clear effect of the layer thickness on the mechanical properties of both bulk material and lattice structures. Instead, the printing direction effect, negligible in solid samples, becomes relevant in lattice structures, yielding different stiffnesses of struts and nodes. This phenomenon is accounted for in the proposed simulation framework. The numerical models of large arrays, used to define the scaling laws, suggest that the chosen topologies have a mainly stretching-dominated behavior─a hallmark of structurally efficient structures─where the modulus scales linearly with the relative density. By looking ahead, mimicking the characteristic microscale structure of crystalline materials will allow replicating the typical behavior of crystals at a larger scale, combining the hardening traits of metallurgy with the characteristic behavior of polymers and the advantage of lightweight architected structures, leading to novel materials with multiple functions.

Rapid Production of Multifunctional Self-Assembling Peptides for Incorporation and Visualization within Hydrogel Biomaterials.

Peptides are of continued interest for therapeutic applications, from soluble and immobilized ligands that promote desired binding or uptake to self-assembled supramolecular structures that serve as scaffolds in vitro and in vivo. These applications require efficient and scalable synthetic approaches because of the large amounts of material that often are needed for studies of bulk material properties and their translation. In this work, we establish new methods for the synthesis, purification, and visualization of assembling peptides, with a focus on multifunctional collagen mimetic peptides (mfCMPs) relevant for formation and integration within hydrogel-based biomaterials. First, a methodical approach useful for the microwave-assisted synthesis of assembling peptide sequences prone to deletions was established, beginning with the identification of the deleted residues and their locations and followed by targeted use of dual chemistry couplings for those specific residues. Second, purification techniques that integrate the principles of heating and ion displacement with traditional chromatography and dialysis were implemented to improve separation and isolation of the desired multifunctional peptide product, which contained blocks for thermoresponsiveness and ionic interactions. Third, an approach for fluorescent labeling of these mfCMPs, which is orthogonal to their assembly and their covalent incorporation into a bulk hydrogel material, was established, allowing visualization of the resulting hierarchical fibrillar structures in three dimensions within hydrogels using confocal microscopy. The methods presented in this work allow the production of multifunctional peptides in scalable quantities and with minimal deletions, enabling future studies for better understanding of composition-structure-property relationships and for translating these biomaterials into a range of applications. Although mfCMPs are the focus of this work, the methods demonstrated could prove useful for other assembling peptide systems and for the production of peptides more broadly for therapeutic applications.

Beyond surface nanoindentation: Combining static and dynamic nanoindentation to assess intrinsic mechanical properties of chemical vapor deposition amorphous silicon oxide (SiOx) and silicon oxycarbide (SiOxCy) thin films

Nanoindentation is a well-known technique to assess the mechanical properties of bulk materials and films. Despite that, nanoindentation of thin films is not straightforward, given that the measured properties are composite information from a film/substrate system and depend on the indentation depth. By using dynamic indentation experiments and analytical or empirical models, we assessed the intrinsic film properties of chemical vapor deposited silicon oxide (SiOx) and silicon oxycarbide (SiOxCy) thin films with thicknesses ranging from 60 to 700 nm. In this work, the Bec rheological model and several mixing laws were reviewed. Measured Young modulus appeared to be affected by the substrate properties more than hardness: for the thinnest films, moduli were measured at ca. 90 GPa whereas intrinsic moduli were calculated at ca. 50 GPa. Using calculated intrinsic film modulus and hardness, it was possible to establish correlations between these properties, the chemical composition and the structural organization of the films.

A review of surface roughness impact on dielectric film properties

The importance of surface roughness with respect to the bulk properties of dielectric materials is often overlooked. Surface roughness or interfaces between different material layers often significantly affects the external properties of thin films. Surface roughness holds its commonalty and critical impact among many materials properties. This review summarises the recent work on the effect of surface roughness on the mechanical, thermal, physical, and dielectric properties of dielectric films. Appropriate roughness favours adhesion, filtration, biological fouling, tribological properties, and magnetic properties. Nevertheless, lower roughness generally benefits the dielectric properties of dielectric materials, with thicknesses ranging from a few nanometres to up to 50 μm. This review discusses surface roughness control and the techniques of measurement as well. It emphasises the importance and characterisation of sample surface roughness for a better understanding of the dielectric phenomenon, mechanisms, and electrical stress test setup for various dielectric films.

Characteristic singular behaviors of nodal-line materials emerging in orbital magnetic susceptibility and Hall conductivity

The bulk properties of nodal line materials have been an important research topic in recent years. In this paper, we study the orbital magnetic susceptibility and the Hall conductivity of nodal line materials using the formalism with thermal Green's functions and find characteristic singular behaviors of them. It is shown that, in the vicinity of the gapless nodal line, the orbital magnetic susceptibility shows a $\delta$-function singularity and the Hall conductivity shows a step function behavior in their chemical potential dependences. Furthermore, these singular behaviors are found to show strong field angle dependences corresponding to the orientation of the nodal line in the momentum space. These singular behaviors and strong angle dependences will give clear evidence for the presence of the nodal line and its orientation and can be used to experimentally detect nodal line materials.

Resolving Site-Specific Energy Levels of Small-Molecule Donor-Acceptor Heterostructures Close to Metal Contacts.

The active material of optoelectronic devices must accommodate for contacts which serve to collect or inject the charge carriers. It is the purpose of this work to find out to which extent properties of organic optoelectronic layers change close to metal contacts compared to known properties of bulk materials. Bottom-up fabrication capabilities of model interfaces under ultrahigh vacuum and single-atom low temperature (LT)-STM spectroscopy with density functional theory (DFT) calculations are used to detect the spatial modifications of electronic states such as frontier-orbitals at interfaces. The system under consideration is made of a silver substrate covered with a blend of C60 and ZnPc molecules of a few monolayers. When C60 and ZnPc are separately adsorbed on Ag(111), they show distinct spectroscopic features in STM. However, when C60 is added to the ZnPc monolayer, it shows scanning tunneling spectra similar to ZnPc, revealing a strong interaction of C60 with the ZnPc induced by the substrate. DFT calculations on a model complex confirm the strong hybridization of C60 with ZnPc layer upon adsorption on Ag(111), thus highlighting the role of boundary layers where the donor-acceptor character is strongly perturbed. The calculation also reveals a significant charge transfer from the Ag to the complex that is likely responsible for a downward shift of the molecular LUMO in agreement with the experiment.

MechElastic: A Python library for analysis of mechanical and elastic properties of bulk and 2D materials

The MechElastic Python package evaluates the mechanical and elastic properties of bulk and 2D materials using the elastic coefficient matrix (Cij) obtained from any ab-initio density-functional theory (DFT) code. The current version of this package reads the output of VASP, ABINIT, and Quantum Espresso codes (but it can be easily generalized to any other DFT code) and performs the appropriate post-processing of elastic constants as per the requirement of the user. This program can also detect the input structure's crystal symmetry and test the mechanical stability of all crystal classes using the Born-Huang criteria. Various useful material-specific properties such as elastic moduli, longitudinal and transverse elastic wave velocities, Debye temperature, elastic anisotropy, 2D layer modulus, hardness, Pugh's ratio, Cauchy's pressure, Kleinman's parameter, and Lame's coefficients, can be estimated using this program. Another existing feature of this program is to employ the ELATE package (2016) [29] and plot the spatial variation of several elastic properties such as Poisson's ratio, linear compressibility, shear modulus, and Young's modulus in three dimensions. Further, the MechElastic package can plot the equation of state (EOS) curves for energy and pressure for a variety of EOS models such as Murnaghan, Birch, Birch-Murnaghan, and Vinet, by reading the inputted energy/pressure versus volume data obtained via numerical calculations or experiments. This package is particularly useful for the high-throughput analysis of elastic and mechanical properties of materials. Program summaryProgram Title:MechElasticCPC Library link to program files:https://doi.org/10.17632/y9zc7zybrm.1Developer's repository link:https://github.com/romerogroup/MechElasticLicensing provisions: GPLv3Programming language: PythonNature of problem: To automatize and simplify the analysis of elastic and mechanical properties for bulk and 2D materials, especially for high-throughput DFT calculations.Solution method: This Python program addresses the above problem by parsing the elastic coefficient matrix obtained from the first-principles DFT calculations, does the appropriate post-processing to evaluate the elastic properties, and performs the mechanical stability tests for all crystal classes using the generalized Born-Huang criteria. It can also be used to carry out the equation of state analysis to study the structural phase transitions.Additional comments:MechElastic can be downloaded using the below link: https://github.com/romerogroup/MechElasticInstallation (via PyPI): pip install mechelastic, or pip3 install mechelastic

Non-polynomial framework for bending responses of the multi-scale hybrid laminated nanocomposite reinforced circular/annular plate

This survey addresses the non-polynomial framework for bending responses of three-phase multi-scale hybrid laminated nanocomposite (MHLNC) reinforced circular/annular plates (MHLNCRCP/ MHLNCRAP) based upon the three-dimensional theory of elasticity for various sets of boundary conditions. The sandwich structure with two, three, five, and seven layers is modeled using compatibility conditions. The state-space based differential quadrature method (SS-DQM) is presented to examine the bending behavior of MHLNCRCP/ MHLNCRAP by considering various boundary conditions. Halpin–Tsai equations and fiber micromechanics are used in the hierarchy to predict the bulk material properties of the multi-scale composite. Singular point is investigated for modeling the annular disk. The carbon nanotubes (CNTs) are supposed to be randomly oriented and uniformly distributed through an epoxy resin matrix. Afterward, a parametric study is done to present the effects of various symmetric cross-ply laminated layers, various types of sandwich circular/annular plates, and various types of pressure on the bending characteristics of the MHLNCRCP/ MHLNCRAP. Numerical results reveal that sinusoidal load is the best pressure for improving the nanocomposite circular/annular plates’ deformation resistance and stress.

A novel method for determination of surface treatment effect on mechanical properties of titanium bulk material

Improving the mechanical properties of the material surface has been the main aim of the researchers for a long time. Utilizing of mechanical treatment procedures, such as direct impact, has been widely used for the bulk materials, but determination of the change in the mechanical properties of impacted material has not been exactly investigated. The main novelty of this paper is the determination of the effect of mechanical treatments on the mechanical properties of bulk materials. For this purpose, the new developed combined algorithm of modified dimensional analysis and minimum resultant error methods were emerged with FEA and experimental data. The finite element analysis (FEA) included the analysis of the impact with nanoindentation in a continued procedure to allow the investigation of the impact on the results of the nanoindentation. Previously, this trend had not been applied to analyze such phenomenon. The challenges of preparing a perfect analysis model to suit the nanoscale process (nanoindentation) and macro process (ball impact) were another investigation field of this research work. The result of this research was a complete calculation of the parameters of Johnson–Cook constants for titanium (Ti) bulk material including the most important strain rate coefficient (C). Comparison of Ti mechanical characteristics shows high improvement in yield stress (24%) against lower change in the elastic modulus (1.2%).

A new predictive model for normal and compound impact wear

This work presents a new model that predicts the wear that results from impacts occurring between two solid bodies under both normal and compound impact, a capability lacking from existing approaches. This frequently occurs in many engineering and industrial situations and depending on the relative sizes of the bodies, bulk material properties, and the number and frequency of impacts, damage can result. Although this eventually causes severe wear problems that limit service life, it is one of the least investigated types of primary wear mechanism. Due to this, robust data, and validated models derived from that data, are rare.The new model considers the contact with respect to shear force. It can predict wear volume loss and be used to improve understanding of the role of different impact angles during impact, and thus inform the design of machines, however it is currently valid for ductile materials only since hardness is a parameter. Empirical inputs to the model were developed using data produced specifically for this work. Predictions made by the model were then validated, with good correlation, for three common metal alloys by means of comparison with experimental data available in the literature.

Bending fracture of ultra-thin plates with surface elasticity containing a thickness-through crack

The bending fracture of an ultra-thin plate containing a thickness-through crack with consideration of surface elasticity is studied in this paper. Based on the Kirchhoff plate theory incorporating surface elasticity, a governing equation is derived for static bending of nanoplates with surface elasticity. The fracture problem of an infinite isotropic elastic nanoplate with a thickness-through crack is presented and solved when the plate is subjected to uniform bending moment, twisting moment, and out-of-plane tearing load, respectively. The Fourier integral transform is applied to solve associated mixed boundary value problems. A hypersingular integral equation is deduced and an exact solution is determined for each case. Complete elastic fields at any position of the nanoplate are given explicitly in terms of elementary functions and the expressions for the intensity factors of stress, shear force, and bending/twisting moment at the crack tips are obtained in closed form. The intensity factors of stress and moment exhibit a square-root singularity, while the effective shear force intensity factors have an r-3/2 singularity near the crack tips, r being the distance from the crack tip. Results are presented graphically to show that the stress intensity factors (SIFs) are related to the bulk and surface material properties. When neglecting surface elasticity, the obtained size-dependent SIFs reduce to the well-known classical counterparts.

Sexual differences in bone porosity, osteocyte density, and extracellular matrix organization due to osteoblastic-specific Bmp2 deficiency in mice.

Clinical studies have come to conflicting conclusions regarding BMP2 deficiency's link to regulating bone mass and increasing fracture risk. This may be due to the signaling protein having sex- or age-dependent effects. Previous pre-clinical studies have supported a role, but have not adequately determined the physical mechanism causing altered bulk material properties. This study investigated the physical effects of Bmp2 ablation from osteogenic lineage cells (Osx-Cre; Bmp2fl/fl) in 10- and 15-week-old male and female mice. Bones collected post-mortem were subjected to fracture toughness testing, reference point indentation testing, microCT, and histological analysis to determine the multi-scale relationships between mechanical/material behavior and collagen production, collagen organization, and bone architecture. BMP2-deficient bones were smaller, more brittle, and contained more lacunae-scale voids and cortical pores. The cellular density was significantly increased and there were material-level differences measured by reference point indentation, independently of collagen fiber alignment or organization. The disparities in bone size and in bone fracture toughness between genotypes were especially striking in males at 15-weeks-old. Together, this study suggests that there are sex- and age-dependent effects of BMP2 deficiency. The results from both sexes also warrant further investigation into BMP2 deficiency's role in osteoblasts' transition to osteocytes and overall bone porosity.

Probing adsorbates on La1−x Sr x NiO3−δ surfaces under humid conditions: implications for the oxygen evolution reaction

Earth-abundant nickel-containing perovskite oxides (ANiO3) are highly active materials for the oxygen evolution reaction (OER). The strong nickel-oxygen (Ni–O) covalency, tunable by A-site chemical substitution, contributes to both bulk and surface material properties like the formation of oxygen vacancies (v •• O ) and OER activity. Here we quantify the coverage of OER relevant adsorbates on a series of La1−x Sr x NiO3−δ (LSNO, 0 ⩽ x ⩽ 0.5) epitaxial thin films exposed to humid environments by ambient pressure x-ray photoelectron spectroscopy. While all LSNO film compositions investigated here have comparable hydroxide coverages at the relative humidities (RHs) probed (1.5 × 10−5 – 0.2%RH), the amount of under-coordinated surface oxygen increases notably with Sr content. We interpret differences in the free energy of adsorption (ΔG ads,i ) of these OER intermediates, inferred from adsorption isotherms, in the context of proposed v •• O -mediated OER mechanisms, consistent with the pH-dependent OER activity observed here for LSNO. We find that Sr incorporation enhances the affinity of LSNO surfaces for these under-coordinated oxygen species, in line with calculations in the literature.

Hard X-ray transient grating spectroscopy on bismuth germanate

Optical-domain transient grating (TG) spectroscopy is a versatile background-free four-wave-mixing technique that is used to probe vibrational, magnetic and electronic degrees of freedom in the time domain1. The newly developed coherent X-ray free-electron laser sources allow its extension to the X-ray regime. X-rays offer multiple advantages for TG: their large penetration depth allows probing the bulk properties of materials, their element specificity can address core excited states, and their short wavelengths create excitation gratings with unprecedented momentum transfer and spatial resolution. Here, we demonstrate TG excitation in the hard X-ray range at 7.1 keV. In bismuth germanate (BGO), the non-resonant TG excitation generates coherent optical phonons detected as a function of time by diffraction of an optical probe pulse. This experiment demonstrates the ability to probe bulk properties of materials and paves the way for ultrafast coherent four-wave-mixing techniques using X-ray probes and involving nanoscale TG spatial periods.

Plasma Mediated Chlorhexidine Immobilization onto Polylactic Acid Surface via Carbodiimide Chemistry: Antibacterial and Cytocompatibility Assessment.

The development of antibacterial materials has great importance in avoiding bacterial contamination and the risk of infection for implantable biomaterials. An antibacterial thin film coating on the surface via chemical bonding is a promising technique to keep native bulk material properties unchanged. However, most of the polymeric materials are chemically inert and highly hydrophobic, which makes chemical agent coating challenging Herein, immobilization of chlorhexidine, a broad-spectrum bactericidal cationic compound, onto the polylactic acid surface was performed in a multistep physicochemical method. Direct current plasma was used for surface functionalization, followed by carbodiimide chemistry to link the coupling reagents of N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDAC) and N-Hydroxysuccinimide (NHs) to create a free bonding site to anchor the chlorhexidine. Surface characterizations were performed by water contact angle test, X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The antibacterial activity was tested using Staphylococcus aureus and Escherichia coli. Finally, in vitro cytocompatibility of the samples was studied using primary mouse embryonic fibroblast cells. It was found that all samples were cytocompatible and the best antibacterial performance observed was the Chlorhexidine immobilized sample after NHs activation.

Cellulose Nanocrystal Liquid Crystal Phases: Progress and Challenges in Characterization Using Rheology Coupled to Optics, Scattering, and Spectroscopy.

Cellulose nanocrystals (CNCs) self-assemble and can be flow-assembled to liquid crystalline orders in a water suspension. The orders range from nano- to macroscale with the contributions of individual crystals, their micron clusters, and macroscopic assemblies. The resulting hierarchies are optically active materials that exhibit iridescence, reflectance, and light transmission. Although these assemblies have the potential for future renewable materials, details about structures on different hierarchical levels that span from the nano- to the macroscale are still not unraveled. Rheological characterization is essential for investigating flow properties; however, bulk material properties make it difficult to capture the various length-scales during assembly of the suspensions, for example, in simple shear flow. Rheometry is combined with other characterization methods to allow direct analysis of the structure development in the individual hierarchical levels. While optical techniques, scattering, and spectroscopy are often used to complement rheological observations, coupling them in situ to allow simultaneous observation is paramount to fully understand the details of CNC assembly from liquid to solid. This Review provides an overview of achievements in the coupled analytics, as well as our current opinion about opportunities to unravel the structural distinctiveness of cellulose nanomaterials.