Next Article in Journal
A Novel Codeword Selection Scheme for MIMO-MAC Lower-Bound Maximization
Next Article in Special Issue
Entropy-Based Feature Extraction for Electromagnetic Discharges Classification in High-Voltage Power Generation
Previous Article in Journal / Special Issue
Residual Multiparticle Entropy for a Fractal Fluid of Hard Spheres
Open AccessArticle

Photons Probe Entropic Potential Variation during Molecular Confinement in Nanocavities

1
National Hellenic Research Foundation, Theoretical and Physical Chemistry Institute, 48 Vassileos Constantinou Avenue, 11635 Athens, Greece
2
Department of Chemistry, Laboratory of Industrial Chemistry, University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece
3
Institute of Physics, Kazan Federal University, 18 Kremljovskaja str., Kazan 420008, Russia
*
Authors to whom correspondence should be addressed.
Entropy 2018, 20(8), 545; https://doi.org/10.3390/e20080545
Received: 12 July 2018 / Revised: 20 July 2018 / Accepted: 21 July 2018 / Published: 24 July 2018
(This article belongs to the Special Issue Entropy: From Physics to Information Sciences and Geometry)
In thin polymeric layers, external molecular analytes may well be confined within tiny surface nano/microcavities, or they may be attached to ligand adhesion binding sites via electrical dipole forces. Even though molecular trapping is followed by a variation of the entropic potential, the experimental evidence of entropic energy variation from molecular confinement is scarce because tiny thermodynamic energy density diverseness can be tracked only by sub-nm surface strain. Here, it is shown that water confinement within photon-induced nanocavities in Poly (2-hydroxyethyl methacrylate), (PHEMA) layers could be trailed by an entropic potential variation that competes with a thermodynamic potential from electric dipole attachment of molecular adsorbates in polymeric ligands. The nano/microcavities and the ligands were fabricated on a PHEMA matrix by vacuum ultraviolet laser photons at 157 nm. The entropic energy variation during confinement of water analytes on the photon processed PHEMA layer was monitored via sub-nm surface strain by applying white light reflectance spectroscopy, nanoindentation, contact angle measurements, Atomic Force Microscopy (AFM) imaging, and surface and fractal analysis. The methodology has the potency to identify entropic energy density variations less than 1 pJm−3 and to monitor dipole and entropic fields on biosurfaces.
View Full-Text
Keywords: entropy; nanothermodynamics; nanoindentation; Atomic Force Microscopy; electric dipole interactions; 157 nm laser; fractal analysis; water contact angle; PHEMA; white light reflectance spectroscopy entropy; nanothermodynamics; nanoindentation; Atomic Force Microscopy; electric dipole interactions; 157 nm laser; fractal analysis; water contact angle; PHEMA; white light reflectance spectroscopy
Show Figures

Graphical abstract

MDPI and ACS Style

Gavriil, V.; Chatzichristidi, M.; Kollia, Z.; Cefalas, A.-C.; Spyropoulos-Antonakakis, N.; Semashko, V.V.; Sarantopoulou, E. Photons Probe Entropic Potential Variation during Molecular Confinement in Nanocavities. Entropy 2018, 20, 545.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop