Programmable Birefringent Patterns from Modulating the Localized Orientation of Cellulose Nanocrystals

Abstract

Birefringence has been attracting broad attention due to its strong potential for applications in biomedicine and optics, such as biomedical diagnosis, colorimetric sensing, retardant, and polarization encoding. However, engineering architectures with precisely controllable birefringence remains a challenge due to the lack of effective modulation of the localized orientation. Here, by taking advantage of the inherently one-dimensional (1D) anisotropic structure of cellulose nanocrystals (CNCs), we demonstrate an approach to tune the alignment of CNCs with a well-controllable orientation at localized preciseness, which is in contrast to the previously reported unidirectional/radical orientation of CNC-based birefringent structures. The localized modulation of CNC orientation is facilitated by directing the 1D nanocrystals to align along the template periphery and the migrated three-phase contact line during the evaporation. The resultant CNC films exhibit birefringent extinction patterns under polarized light, in which versatile pattern designs can be obtained by employing templates with different shapes and template arrays with varied layouts. Due to the locally modulated orientation of CNCs, the films indicate “kaleidoscope-like” dynamically transformable designs of the birefringent patterns depending on the polarized angle, which has barely been observed previously. Furthermore, an N-nary encoding system for abundant information storage is demonstrated based on the sunlight-transparent CNC films, but with visible extinction patterns under polarized light, which is promising for encryptions, anticounterfeiting, and imaging, enriching the attractive research area of bio-based photonics.

Evaporation-induced self-assembly of liquid crystal biopolymers

“…9d). 93 The CNCs-PVA composite could be designed as a beautiful structure based on controlling the surface tension gradient on the embossed pattern. The M-CNCs forming the full concentric alignment in the sessile droplet formed various structures that the contact lines fixed by the template determine the alignment of the M-CNCs, which induces surface tension gradients depending on their shape.…”

“…9b and c). 92,93 This journal is © The Royal Society of Chemistry 2024 (i) Introduction of additives. The water-soluble additives increase solution viscosity when mixing with the CNCs.…”

Plasmonic metasurfaces of cellulose nanocrystal matrices with quadrants of aligned gold nanorods for photothermal anti-icing

“…Recently, several potential solutions have been suggested to achieve uniformity, i.e., (i) solutal-Marangoni flows generated by a volatile vapor-saturated environment 23 , 24 , (ii) thermal-Marangoni effects on a heated solid substrate 25 , 26 , and (iii) viscosity enhancement by gelation 27 , 28 . But, unfortunately, each method has limitations.…”

Macromolecular Metamorphosis in a Polymer Network via the Reversible Collapse of Single-Chain Nanoparticles

“…Recently, in the pursuit of ever more dramatic stimulus-induced property modifications, macromolecular metamorphosis within PNs has attracted increasing attention, as such materials can bring about significant changes in performance. One of the strategies to obtain these smart materials is to introduce topologically transformable polymers (i.e., changes due to the rearrangement of constituent parts to achieve a new chain architecture) into a network. − For example, Sumerlin and colleagues used a diene displacement reaction to trigger a thermal transition in the network architecture, which considerably enhanced the elasticity of gels. Among the various architecture-transformable polymers, single-chain polymer nanoparticles (SCNPs) are regarded as specific architecture-switchable polymers, in which folding the single-chain polymer chains into SCNPs on demand is a popular model for simulating the controlled folding of biomacromolecules. − Typically, SCNPs can be constructed via supramolecular, dynamic, or covalent interactions.…”