Nanoparticle adsorption induced configurations of nematic liquid crystal droplets

Sengul S., AYDOĞAN N., BÜKÜŞOĞLU E.

JOURNAL OF COLLOID AND INTERFACE SCIENCE, cilt.608, ss.2310-2320, 2022 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 608
  • Basım Tarihi: 2022
  • Doi Numarası: 10.1016/j.jcis.2021.10.156
  • Dergi Adı: JOURNAL OF COLLOID AND INTERFACE SCIENCE
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Applied Science & Technology Source, CAB Abstracts, Chimica, Compendex, EMBASE, INSPEC, MEDLINE, Veterinary Science Database
  • Sayfa Sayıları: ss.2310-2320
  • Anahtar Kelimeler: Liquid crystals, Nanoparticles, Adsorption, Response, Emulsions, GOLD NANOPARTICLES, AQUEOUS PHASES, SURFACES, INTERFACES, MICROMETER, PROTEINS, MICROPARTICLES, MICRODROPLETS, ORIENTATION, AMPHIPHILES
  • Hacettepe Üniversitesi Adresli: Evet

Özet

Nematic liquid crystal (LC) droplets have been widely used for the detection of molecular species. We investigate the response of micrometer sized nematic LC droplets against the adsorption of nanoparticles from aqueous media. We synthesized ti 100 nm-in-diameter silica nanoparticles and modified their sur-faces to mediate either planar or homeotropic LC anchoring and a pH-dependent charge. We show sur -face functionality-and concentration-dependent configurations of the droplets consistent with the change in the surface anchoring and the formation of local heterogeneities upon adsorption of the nanoparticles to LC-aqueous interfaces. The adsorption of nanoparticles modified with dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DMOAP, homeotropic) exhibit a transition from bipolar to radial, whereas the adsorption of -COOH-terminated counterparts (planar) did not cause a configura-tion transition. By manipulating the electrostatic interactions, we controlled the adsorption of the nanoparticles to the LC-aqueous interfaces, providing access to the physicochemical properties of the nanoparticles. We demonstrate a temporal change in the droplet configurations caused by the adsorption of the nanoparticles functionalized with -COOH/DMOAP mixed monolayers. These results provide a basis for studies in applications for the detection of nano-sized species, for sensing applications that combine nanoparticles with LCs, and for the synthesis of anisotropic composite particles with complex structures. (c) 2021 Elsevier Inc. All rights reserved.