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Evidence of pattern formation in the Langmuir Reverse Schaefer films of liquid crystal incubated in silver nanocolloids: A combined experimental and theoretical study

Priyabrata Maity and Joydeep Chowdhury*

  • *Contact author: joydeep.chowdhury@jadavpuruniversity.in; joydeep72_c@rediffmail.com
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APS Open Sci. 1, 000177 – Published 22 October, 2026

DOI: https://doi.org/10.1103/6nzw-jcrg

Abstract

Spontaneous pattern formation at unstable fluid-fluid interfaces is a popular feature of nonequilibrium systems, often arising from the interplay between interfacial tension and hydrodynamic instabilities. One of the most prominent examples is viscous fingering in quasi-two-dimensional Hele-Shaw geometries, where the displacement of a more viscous fluid by a less viscous one produces highly branched, dendritic morphologies. In this work, we report the formation of nearly dendritic patterns in Langmuir Reverse Schaefer (L-RSh) films of the nematic liquid crystal N-(4-methoxybenzylidene)-4-butylaniline (MBBA) upon incubation with silver nanocolloids (AgNcs) of average diameter ∼30 nm, whereas linear stripelike structures are observed for larger nanoparticles (∼64 nm) on the same L-RSh film of MBBA molecules. The origin of this size-dependent morphological transition is interpreted in terms of topological defects generated due to the incorporation of metal nanoparticles within the continuum L-RSh liquid crystal matrix. A comprehensive statistical characterization of the patterned substrate has been carried out through parameters such as lateral correlation length (ξ), fractal dimension (D), Hurst exponent (β), and interface width (ω). Further insights into the complexity of the patterns reveal their multifractal nature, evaluated using two-dimensional multifractal detrended fluctuation analysis. To the best of our knowledge, this study appears to be the first report where thorough investigations on the surface properties of the as-prepared patterned substrate have been discussed in detail. Finally, the patterned substrate demonstrates the good performance as surface-enhanced Raman scattering platforms, enabling detection of rhodamine 6G and 1,10-phenanthroline molecules at extremely low concentrations.

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APS Open Sci. 1, 000177– Published 22 October, 2026
Vol. 1
  • Received 13 April 2026
  • Accepted 1 October 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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