Nematic dispersions of nanoporous silica hollow spheres with potential for smart window applications

Chen, Wei-Ting (author), Čopar, Simon (author), Žumer, Slobodan (author)

Nanoporous silica hollow spheres (NPSHSs) with a microscale diameter and high roughness of outer and inner surfaces can be well suspended in a nematic liquid crystal (NLC). Nanopores allow nematics to fill the NPSHS and form inner nematic droplets with an order due to the randomness of pores uncorrelated with outer nematic ordering. Due to the nanoconfinement effect and the strong local anchoring of rough nanostructure on the NPSHS surface, the binary mixture of nematic molecules and NPSHSs demonstrates the effectiveness of nanomorphology on aggregation suppression. The calorimetry showed a decrease in nematic transition enthalpy; optical microscopy indicated decoupled nematic ordering inside and outside NPSHSs, characterized by bubbles, and laser tweezers helped to identify a reduction of the minimum intershell distance for notable attractive interactions. In line with the observations, simulations prove the existence of disordered NLC layers on the NPSHS surfaces characterized by weak effective planar degenerate nematic anchoring. The resulting aggregation suppression, negligible gravitational sedimentation due to nanoshell lightness, and decoupling of inner and outer nematics to offer their separate manipulation are promising for optoelectronic applications of NLC dispersions of NPSHSs. We illustrate that together with their high chemical stability, these dispersions open possibilities for applications in smart windows based on LC-controlled transparency, where more scattering domains can enhance tunability and contrast.

• Language: English
• Keywords: nematic liquid crystals, nanoparticles, nanopores
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: Str. 20858−20869
• Numbering: Vol. 8, iss. 43
• PID: 20.500.12556/RUL-180358
• UDC: 538.9
• ISSN on article: 2574-0970
• DOI: 10.1021/acsanm.5c03511
• COBISS.SI-ID: 270749443
• Publication date in RUL: 06.03.2026

Record is a part of a journal

• Title: ACS applied nano materials
• Shortened title: ACS appl. nano mater.
• Publisher: American Chemical Society
• ISSN: 2574-0970
• COBISS.SI-ID: 32649255

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: nematski tekoči kristali, nanodelci, nanopore