Research Data supporting "Angular optical response of cellulose nanocrystal films explained by the distortion of the arrested suspension upon drying"

The data are organized and grouped in dedicated .zip files for each Figure they contribute to. All figures (1-21) are present in high resolution in each sub-folder. Software for file extensions: .tif, .png (image format), .m and .fig (MATLAB), text files (.txt). For further details, see the file "Open data summary"

Research data supporting "Hyperspectral Imaging of Photonic Cellulose Nanocrystal Films: Structure of Local Defects and Implications for Self-Assembly Pathways"

raw data sorted by Figures for both the main body and the supporting information, as detailed in the explanatory .pd

Retrieving the Coassembly Pathway of Composite Cellulose Nanocrystal Photonic Films from their Angular Optical Response.

Aqueous suspensions of cellulose nanocrystals (CNCs) are known to self-assemble into a chiral nematic liquid crystalline phase, leading to solid-state nanostructured colored films upon solvent evaporation, even in the presence of templating agents. The angular optical response of these structures, and therefore their visual appearance, are completely determined by the spatial arrangement of the CNCs when the drying suspension undergoes a transition from a flowing and liquid crystalline state to a kinetically arrested state. Here, it is demonstrated how the angular response of the final film allows for retrieval of key physical properties and the chemical composition of the suspension at the onset of the kinetic arrest, thus capturing a snapshot of the past. To illustrate this methodology, a dynamically evolving sol-gel coassembly process is investigated by adding various amounts of organosilica precursor, namely, 1,2-bis(trimethoxysilyl)ethane. The influence of organosilica condensation on the kinetic arrest can be tracked and thus explains the angular response of the resulting films. The a posteriori and in situ approach is general; it can be applied to a variety of additives in CNC-based films and it allows access to key rheological information of the suspension without using any dedicated rheological technique.M.J.M. thanks NSERC for a Discovery Gran

Controlled, Bio-inspired Self-Assembly of Cellulose-Based Chiral Reflectors.

The self-assembly process of photonic structures made of cellulose nanocrystals is studied in detail by locally monitoring and controlling water evaporation. Three different stages during the evaporation process are identified. Spectroscopy quantifies the amount of disorder in the fabricated samples. Control of this process enables the selection of a range of different colors starting from the same suspension, providing a facile, sustainable route for the manufacture of structural color

Research data supporting "Retrieving the co-assembly pathway of composite cellulose nanocrystal photonic films from their angular optical response"

the Summary of the data is detailed in the provided document "OpenDataSummary.pdf" and ordered by the figures they contributed to, including for the Figures in Supporting Information.M.J.M. thanks NSERC for a Discovery Grant

Research data supporting “Bio-compatible and Sustainable Optical Strain Sensors for Large-area applications”

Original or unprocessed data is provided in support of the article “Bio-compatible and Sustainable Optical Strain Sensors for Large-area applications”. The data is structured into six folders, each correlating to a specific data type presented in the published article. The folders are named according to the figures, which the contained data were taken from, except for the “supplementary” folder (data of 6 figures in one folder). All data are saved as plain text (csv format) with a file name indicating the corresponding figure and the nature of data, for example spectral data of Figure 1a would be stored in folder “fig1” with a file name of “a_spectra.txt”. fig1: Intensity values of the spectra shown in Fig 1f and their corresponding wavelength are provided. fig2: Intensity values of the spectra shown in Fig 2a-c and their corresponding wavelength are provided. fig3: Peak wavelength value shown in Fig 3b and their corresponding angle of detection are provided. fig4: Pitch values shown in Fig 4a,b and stretch ratio values shown in Fig 4c,d, and their corresponding angle of detection are provided. fig5: Normalised peak wavelength values shown in Fig 5a and their corresponding strain values are provided. supplementary: All measurement data shown in the supplementary information are provided.BBSRC David Phillips fellowship [BB/K014617/1] Isaac Newton Trust [76933], ERC [H2020 639088

Surfactant induced bilayer-micelle transition for emergence of functions in anisotropic hydrogel

Tuning the self-assembled structures in amorphous hydrogels will enrich the functionality of hydrogels. In this study, we tuned the structure of a photonic hydrogel, which consists of polymeric lamellar bilayers entrapped inside a polyacrylamide network, simply by molecular triggering using an ionic surfactant. Owing to the binding of ionic surfactants (sodium dodecyl sulfate), the lamellar bilayers comprising of non-ionic polymeric surfactants [poly(dodecyl glyceryl itaconate)] changed to micelles, whereas the unidirectional lamellar structure was preserved in the hydrogel. The bilayer-micelle structure transition caused a dramatic decrease in the swelling anisotropy and mechanical softening of the photonic gel. With the micelle structure, the softened gel shows fast (0.3 s) and reversible color change over the entire visible light range in response to a small mechanical pressure (5 kPa). This low stress-induced color-changing hydrogel could be applied as a visual tactile sensor in various fields, especially in biomedical engineering

In situ observation of a hydrogel-glass interface during sliding friction

Direct observation of hydrogel contact with a solid surface in water is indispensable for understanding the friction, lubrication, and adhesion of hydrogels under water. However, this is a difficult task since the refractive index of hydrogels is very close to that of water. In this paper, we present a novel method to in situ observe the macroscopic contact of hydrogels with a solid surface based on the principle of critical refraction. This method was applied to investigate the sliding friction of a polyacrylamide (PAAm) hydrogel with glass by using a strain-controlled parallel-plate rheometer. The study revealed that when the compressive pressure is not very high, the hydrogel forms a heterogeneous contact with the glass, and a macro-scale water drop is trapped at the soft interface. The pre-trapped water spreads over the interface to decrease the contact area with the increase in sliding velocity, which dramatically reduces the friction of the hydrogel. The study also revealed that this heterogeneous contact is the reason for the poor reproducibility of hydrogel friction that has been often observed in previous studies. Under the condition of homogeneous full contact, the molecular origin of hydrogel friction in water is discussed. This study highlights the importance of direct interfacial observation to reveal the friction mechanism of hydrogels