As an important and interesting question, the delicate influence of confinement effect on properties of fluids in nanopores still needs deeper understanding. To this regard, phase behaviors of normal hexadecane (n-C 16 H 34 , C 16 ) absorbed in porous materials are investigated. Phase transitions of C 16 in SBA-15 (7.8 and 17.2 nm), CPG (8.1 and 300 nm), C-SBA-15 (15.6 nm) (carbon coated), and KIT-6 (8.6 nm) were scanned using differential scanning calorimetry (DSC) and temperature-dependent powder X-ray diffraction (XRD) in cooling and heating processes. The bulk C 16 is known to form a transient rotator phase R I on cooling. In this work, freezing and melting points of C 16 in the nanopores are found to be depressed. C 16 in the large pores of CPG (300 nm) only shows a triclinic phase. In the pores of diameters d = 7.8−17.2 nm, C 16 exhibits stable or metastable rotator phase R I or R II . The stabilization of the rotators by nanoconfinement is more obvious in smaller pores or with stronger pore surface interactions due to the significant contributions of interface energy of the nanosized crystals. From structural analysis, hexadecane solid in the large pores retains a complete lamellar structure, whereas the packing of molecules is heavily disturbed in the smaller pores (d < 20 nm). The phase information on the pore C 16 can help understanding the influence of size effect, interface interactions and pore geometry on its physical properties.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.