Measurement of Nanoscale Interfacial Contact Area Using Vibrational Spectroscopy

Fuente: arXiv
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Main Authors: Patil, Utkarsh, Merriman, Stephen, Kumar, Shubhendu, Dhinojwala, Ali
Format: Preprint
Published: 2024
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author Patil, Utkarsh
Merriman, Stephen
Kumar, Shubhendu
Dhinojwala, Ali
author_facet Patil, Utkarsh
Merriman, Stephen
Kumar, Shubhendu
Dhinojwala, Ali
contents Understanding the extent of contact between objects is crucial for surface-driven phenomena in the natural world. While interactions are known to occur at subnanometer-length scales, the techniques needed to measure such small-length scales are lacking. We combined two complementary techniques of attenuated total reflectance infrared (ATR-IR) spectroscopy coupled with an imaging detector and sum frequency generation (SFG) spectroscopy to characterize the real contact area between surfaces. Imaging ATR-IR provides the distribution of airgap separation between the surfaces at larger than molecular length scales as well as an estimation of the real contact area. Additionally, SFG directly probes the intermolecular interactions occurring at molecular scales. Through the combination of these techniques, we show how contact is achieved for both thin, rigid/glassy polymer films on top of soft elastomers and rigid/glassy samples. Interestingly, we also show that the orientation of the molecules in contact is a critically important factor that influences interfacial interactions rather than just the number of molecular sites in contact.
format Preprint
id arxiv_https___arxiv_org_abs_2402_12697
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Measurement of Nanoscale Interfacial Contact Area Using Vibrational Spectroscopy
Patil, Utkarsh
Merriman, Stephen
Kumar, Shubhendu
Dhinojwala, Ali
Soft Condensed Matter
Understanding the extent of contact between objects is crucial for surface-driven phenomena in the natural world. While interactions are known to occur at subnanometer-length scales, the techniques needed to measure such small-length scales are lacking. We combined two complementary techniques of attenuated total reflectance infrared (ATR-IR) spectroscopy coupled with an imaging detector and sum frequency generation (SFG) spectroscopy to characterize the real contact area between surfaces. Imaging ATR-IR provides the distribution of airgap separation between the surfaces at larger than molecular length scales as well as an estimation of the real contact area. Additionally, SFG directly probes the intermolecular interactions occurring at molecular scales. Through the combination of these techniques, we show how contact is achieved for both thin, rigid/glassy polymer films on top of soft elastomers and rigid/glassy samples. Interestingly, we also show that the orientation of the molecules in contact is a critically important factor that influences interfacial interactions rather than just the number of molecular sites in contact.
title Measurement of Nanoscale Interfacial Contact Area Using Vibrational Spectroscopy
topic Soft Condensed Matter
url https://arxiv.org/abs/2402.12697