Dresden 2026 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 23: Biopolymers, Biomaterials and Bioinspired Functional Materials I (joint session CPP/BP)

BP 23.4: Vortrag

Mittwoch, 11. März 2026, 16:00–16:15, ZEU/0255

Cellulose-colloid hybrid materials for refractive index tuning — •Stephan V. Roth — Deutsches Elektronen-Synchrotron DESY, Hamburg, Sweden — KTH Royal Institute of Technology, Stockholm, Sweden

Cellulose nanofibrils (CNF) with tailored (negative) surface charge are ideal for stable, nanoporous, structure-guiding network for thin film composite materials. Colloid materials offer the possibility for tunable structural colors, templates for metamaterials, and refractive index tuning. Here, core-shell-colloids with a hydrophobic core and positively charged, hydrophilic shell are used as additive in CNF thin films to tune their refractive index. The imbibition and self-assembly of the colloids as a function of colloid diameter in the CNF network was quantified, with colloids smaller than the pores in the CNF network penetrating into the thin film. Subsequent heat treatment allows for nanoscale composite formation on the level of the ~ 10 nm sized CNF bundles, while humidity treatment homogenizes the colloid distribution. Furthermore, the influence of the colloid size on the CNF structure inside the thin film was investigated and related to the mechanical properties of the colloid-CNF composite.

Keywords: Cellulose; Core-shell colloids; Hybrid materials; Optical properties; Small-angle X-ray scattering