Controlled, Bio‐inspired Self‐Assembly of Cellulose‐Based Chiral Reflectors

Dumanlı, Ahu Gümrah; Kamita, Gen; Landman, Jasper; Kooij, Hanne M. van der; Glover, Beverley J.; Baumberg, Jeremy J.; Steiner, Ullrich; Vignolini, Silvia

doi:10.1002/adom.201400112

Cited by 203 publications

(190 citation statements)

References 31 publications

(34 reference statements)

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“…[6,40] A xenon lamp (HPX-2000, Ocean Optics) was used as a light source and a spectrometer (AvaSpec-HS2048, Avantes) was used to extract the scattered optical signal. The sample mounted on the goniometer was illuminated with a slightly focused beam.…”

Section: Methodsmentioning

confidence: 99%

“…Such a system can be described in first approximation using the de Vries formula for cholesteric liquid crystals [6,29] np cos λ φ =…”

mentioning

confidence: 99%

“…[1] Many of the cellulose derivatives are commonly used in diverse industrial applications, such as food additives [2] and for biomedical devices [3] due to their non toxic and water soluble nature. Moreover, the self assembly nature [4] and responsiveness [5] of cellulosic biopolymers makes them extremely attractive for smart photonic applications [6,7] including sensing. [8,9] Among various types of cellulose and its derivatives, hydroxypropyl cellulose (HPC) encompasses all these desirable properties, which makes it an extraordinarily multifunctional and versatile material.…”

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confidence: 99%

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Biocompatible and Sustainable Optical Strain Sensors for Large‐Area Applications

Kamita

Frka‐Petesic

Allard

et al. 2016

Advanced Optical Materials

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114

138

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By a simple two-step procedure, large photonic strain sensors using a biocompatible cellulose derivative are fabricated. Transient color shifts of the sensors are explained by a theoretical model that consideres the deformation of cholesteric domains, which is in agreement with the experimental results. The extremely simple fabrication method is suitable for both miniaturization and large-sale manufacture, taking advantage of inexpensive and sustainable materials

show abstract

Section: Methodsmentioning

confidence: 99%

“…Such a system can be described in first approximation using the de Vries formula for cholesteric liquid crystals [6,29] np cos λ φ =…”

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Biocompatible and Sustainable Optical Strain Sensors for Large‐Area Applications

Kamita

Frka‐Petesic

Allard

et al. 2016

Advanced Optical Materials

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114

138

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“…Because of the negative sulfate half-esters or other surface charges remaining from the production procedure, CNCs are easily dispersed in water. Adding their excellent mechanical properties, optical transparency, ease of chemical functionalization, and ability to form a longrange-ordered LC phase, CNCs are highly attractive for the realization of tunable, in some cases even responsive, highperformance materials with spectacular mechanical and optical properties 5,9,[13][14][15] . The LC phase formed by CNC suspensions is of the chiral nematic, or cholesteric, type.…”

Section: Introductionmentioning

confidence: 99%

Fractionation of cellulose nanocrystals: enhancing liquid crystal ordering without promoting gelation

et al. 2018

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Colloids of electrically charged nanorods can spontaneously develop a fluid yet ordered liquid crystal phase, but this ordering competes with a tendency to form a gel of percolating rods. The threshold for ordering is reduced by increasing the rod aspect ratio, but the percolation threshold is also reduced with this change; hence, prediction of the outcome is nontrivial. Here, we show that by establishing the phase behavior of suspensions of cellulose nanocrystals (CNCs) fractionated according to length, an increased aspect ratio can strongly favor liquid crystallinity without necessarily influencing gelation. Gelation is instead triggered by increasing the counterion concentration until the CNCs lose colloidal stability, triggering linear aggregation, which promotes percolation regardless of the original rod aspect ratio. Our results shine new light on the competition between liquid crystal formation and gelation in nanoparticle suspensions and provide a path for enhanced control of CNC self-organization for applications in photonic crystal paper or advanced composites.

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“…If the helix is allowed to reach the short sub-micron range, this can be seen by the naked eye as vivid iridescent colors being reflected from the sample. Typically, this happens when the water of an aqueous suspension of the rods is allowed to evaporate, leaving a thin paper-like film that displays striking colors across the whole visible spectrum (Beck et al, 2011(Beck et al, , 2013Tabor et al, 2012;Gray, 2013;Dumanli et al, 2014;Kelly et al, 2014;Lagerwall et al, 2014;Mu and Gray, 2014;Park et al, 2014). Moreover, due to the helical internal structure, the reflected light is circularly polarized with the same handedness as the helix (Dumanli et al, 2014;Lagerwall et al, 2014;Park et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Equilibrium Liquid Crystal Phase Diagrams and Detection of Kinetic Arrest in Cellulose Nanocrystal Suspensions

et al. 2016

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The cholesteric liquid crystal self-assembly of water-suspended cellulose nanocrystal (CNC) into a helical arrangement was observed already more than 20 years ago, and the phenomenon was used to produce iridescent solid films by evaporating the solvent or via sol-gel processing. Yet, it remains challenging to produce optically uniform films and to control the pitch reproducibly, reflecting the complexity of the three-stage drying process that is followed in preparing the films. An equilibrium liquid crystal phase formation stage is followed by a non-equilibrium kinetic arrest, which in turn is followed by structural collapse as the remaining solvent is evaporated. Here, we focus on the first of these stages, combining a set of systematic rheology and polarizing optics experiments with computer simulations to establish a detailed phase diagram of aqueous CNC suspensions with two different values of the surface charge, up to the concentration where kinetic arrest sets in. We also study the effect of varying ionic strength of the solvent. Within the cholesteric phase regime, we measure the equilibrium helical pitch as a function of the same parameters. We report a hitherto unnoticed change in character of the isotropic-cholesteric transition at increasing ionic strength, with a continuous weakening of the first-order character up to the point where phase coexistence is difficult to detect macroscopically due to substantial critical fluctuations.

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Controlled, Bio‐inspired Self‐Assembly of Cellulose‐Based Chiral Reflectors

Cited by 203 publications

References 31 publications

Biocompatible and Sustainable Optical Strain Sensors for Large‐Area Applications

Biocompatible and Sustainable Optical Strain Sensors for Large‐Area Applications

Fractionation of cellulose nanocrystals: enhancing liquid crystal ordering without promoting gelation

Equilibrium Liquid Crystal Phase Diagrams and Detection of Kinetic Arrest in Cellulose Nanocrystal Suspensions

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