Insights into the Multiscale Lubrication Mechanism of Edible Phase Change Materials.

Content Provider	Europe PMC
Author	Soltanahmadi, Siavash Bryant, Michael Sarkar, Anwesha
Copyright Year	2023
Abstract	Investigation of a lubrication behavior of phase changematerials(PCM) can be challenging in applications involving relative motion, e.g., sport (ice skating), food (chocolates), energy (thermalstorage), apparel (textiles with PCM), etc. In oral tribology, a phasechange often occurs in a sequence of dynamic interactions betweenthe ingested PCM and oral surfaces from a licking stage to a saliva-mixed stage at contact scalesspanning micro- (cellular), meso- (papillae), and macroscales. Oftenthe lubrication performance and correlations across length scalesand different stages remain poorly understood due to the lack of testingsetups mimicking real human tissues. Herein, we bring new insightsinto lubrication mechanisms of PCM using dark chocolate as an exemplarat a single-papilla (meso)-scale and a full-tongue (macro) scale coveringthe solid, molten, and saliva-mixed states, uniting highly sophisticatedbiomimetic oral surfaces with in situ tribomicroscopyfor the first time. Unprecedented results from this study supportedby transcending lubrication theories reveal how the tribological mechanismin licking shifted from solid fat-dominated lubrication (saliva-poorregime) to aqueous lubrication (saliva-dominant regime), the latterresulted in increasing the coefficient of friction by at least threefold.At the mesoscale, the governing mechanisms were bridging of cocoabutter in between confined cocoa particles and fat coalescence ofemulsion droplets for the molten and saliva-mixed states, respectively.At the macroscale, a distinctive hydrodynamic viscous film formedat the interface governing the speed-dependent lubrication behaviorindicates the striking importance of multiscale analyses. New tribologicalinsights across different stages and scales of phase transition fromthis study will inspire rational design of the next generation ofPCM and solid particle-containing materials.
ISSN	19448244
Journal	ACS Applied Materials & Interfaces
Volume Number	15
PubMed Central reference number	PMC9880949
Issue Number	3
PubMed reference number	36633252
e-ISSN	19448252
DOI	10.1021/acsami.2c13017
Language	English
Publisher	American Chemical Society
Publisher Date	2023-01-12
Access Restriction	Open
Rights License	Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). © 2023 The Authors. Published by American Chemical Society
Subject Keyword	soft tribology coalescence aqueous lubrication friction coefficient oral processing papillae chocolate saliva tongue-like surface
Content Type	Text
Resource Type	Article
Subject	Nanoscience and Nanotechnology Medicine Materials Science