Osmotic-Pressure-Induced Nematic Ordering in Suspensions of Laponite and Carboxy Methyl Cellulose

Xu P., YAZICI A. F., ERDEM T., Lekkerkerker H. N. W., MUTLUGÜN E., Eiser E.

JOURNAL OF PHYSICAL CHEMISTRY B, cilt.124, sa.42, ss.9475-9481, 2020 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 124 Sayı: 42
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1021/acs.jpcb.0c06674
  • Dergi Adı: JOURNAL OF PHYSICAL CHEMISTRY B
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Applied Science & Technology Source, Aquatic Science & Fisheries Abstracts (ASFA), Chemical Abstracts Core, Chimica, Compendex, Computer & Applied Sciences, EMBASE, MEDLINE
  • Sayfa Sayıları: ss.9475-9481
  • Abdullah Gül Üniversitesi Adresli: Evet

Özet

Laponite is a synthetic clay that is known to form gels in aqueous suspensions at low concentrations (0.01 g/cm(3)) Although it is expected to form lyotropic liquid crystals, such phases usually do not form, as a consequence of laponite's tendency to form gels at concentrations below the threshold for liquid crystal formation. Here we show that macroscopic, birefringent phases of laponite can be prepared through osmotic compression of a laponite solution by an aqueous solution of carboxy methyl cellulose (CMC). We present polarization imaging studies showing how the initially dilute, isotropic laponite phase shrinks while developing typical birefringence colors between crossed polarizers. Using the MichelLevy interference charts, we were able to extract the refractive index and orientation of the laponite nanodisks in the compressed region. Our observations allow us to propose a tentative state diagram, indicating the concentration regions for which we obtain optically anisotropic gels.