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Abstract The study reports novel photonic properties of Ti3C2TxMXene flakes horizontally self‐assembled within cellulose nanofiber (CNF) matrix exhibiting unique bright multispectral colors combined with overall high transparency in the transmission regime. The intense reflection colors are reflected by individual flakes acting as effective micromirrors with shifts based on their subsurface positioning within the dielectric layers. Unique color appearances are controlled by an interplay of multiple bandgaps formed by constructive and destructive interferences at flake‐matrix interfaces. These colors manifest at the microscale under bright field optical microscopy, while the total physical film retains high transparency up to 85% and a typical greenish hue characteristic of the MXene content below 1% volume fraction. The diverse spectral appearance of 4 µm ultra‐thin films is ultimately controlled by the positioning of the horizontal flakes within the nanofiber matrix at diverse distances from the top surface. This work expands the understanding of thin films with assembled 2D materials within polymer matrix and their fundamental interactions creating new structural coloration functionalities with the potential for multispectral photonic applications such as camouflaging, photothermal treatment, and optical communication for flexible thin bio‐derived films.
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This content will become publicly available on August 4, 2027
Multifunctional Cellulose Nanofiber Films With Embedded Highly Oriented MXene Flakes
ABSTRACT Ultrathin transparent photonic films that are simultaneously robust, cytocompatible, and actively antimicrobial remain rare. Here, the critical physical properties of freestanding micrometer‐thick films composed of layered cellulose nanofibers intercalated with Ti3C2TxMXene nanosheets (CNF‐MXene) are established. Correlated co‐alignment of MXene flakes with near‐perfect in‐plane order is achieved in the cellulose nanofiber matrix by vacuum‐assisted filtration. The Herman's orientation parameter of MXene nanosheets reaches up to 0.94, approaching the theoretical limit of 1.0 for perfect orientational order. Flow‐assisted alignment and nanofiber‐mediated confinement are proposed to suppress MXene restacking and lock the unique film architecture into a stable scaffold. This highly ordered structure yields a significant increase in mechanical strength and elastic modulus. Moreover, co‐alignment of individual flakes at ultralow volume fractions (below 1%) creates accessible, photothermally active surface sites within optically clear films. As a result, these ultrathin CNF‐MXene membranes combine near‐infrared‐activated photothermal antimicrobial behavior and molecular adsorption of organic dye as a proxy for accessibility, highlighting a distinctive multifunctional platform for active bio‐based films with strong potential for wound‐healing applications and long‐term functionality preservation.
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- Award ID(s):
- 2202907
- PAR ID:
- 10704229
- Publisher / Repository:
- Small
- Date Published:
- Journal Name:
- Small
- ISSN:
- 1613-6810
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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