Details
| Original language | English |
|---|---|
| Article number | 114150 |
| Journal | ULTRAMICROSCOPY |
| Volume | 273 |
| Early online date | 18 Apr 2025 |
| Publication status | E-pub ahead of print - 18 Apr 2025 |
Abstract
Surface free energy (SFE) is an important surface property in food processing as it determines the wettability of solid surfaces or the interaction of mould surfaces and chocolate during the moulding process. High-resolution information about SFE could be useful to understand gloss inhomogeneities of chocolates after de-moulding. SFE is connected with adhesion properties. Thus, Atomic force microscopy (AFM) adhesion measurements can be applied to determine SFE of a solid surface at microscopic scale. For this purpose, AFM tips were functionalized to modify their SFE and used for adhesion measurements at three different chocolate gloss areas (matt, glossy and homogenous) via AFM force maps. Influence of relevant parameters such as surface roughness, contact area, relative humidity, and SFE of functionalized tips was considered. Two different mathematical approaches based on Johnson-Kendall-Roberts theory were used to calculate SFE from adhesion values. The measured adhesion values showed variations depending on functionalized tip and chocolate gloss area. The results showed a difference in adhesion and, consequently, SFE in the different gloss areas with gloss > homogenous > matt. However, SFE obtained from adhesion forces were not decisive enough to enable a direct correlation with SFE data from contact angle measurements at the same area.
Keywords
- Adhesion, Atomic force microscopy, Surface free energy, Chocolate gloss inhomogemeities, Functionalized tips, Microscopic scale, Root mean square roughness
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Physics and Astronomy(all)
- Atomic and Molecular Physics, and Optics
- Physics and Astronomy(all)
- Instrumentation
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In: ULTRAMICROSCOPY, Vol. 273, 114150, 07.2025.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Opportunities and challenges to determine surface free energy of chocolates on microscopic scale from atomic force microscopy adhesion measurements
AU - Schroeder, Sarah
AU - Dewettinck, Koen
AU - Heinz, Volker
AU - Bindrich, Ute
AU - Middendorf, Dana
AU - Franke, Knut
N1 - Publisher Copyright: © 2025
PY - 2025/4/18
Y1 - 2025/4/18
N2 - Surface free energy (SFE) is an important surface property in food processing as it determines the wettability of solid surfaces or the interaction of mould surfaces and chocolate during the moulding process. High-resolution information about SFE could be useful to understand gloss inhomogeneities of chocolates after de-moulding. SFE is connected with adhesion properties. Thus, Atomic force microscopy (AFM) adhesion measurements can be applied to determine SFE of a solid surface at microscopic scale. For this purpose, AFM tips were functionalized to modify their SFE and used for adhesion measurements at three different chocolate gloss areas (matt, glossy and homogenous) via AFM force maps. Influence of relevant parameters such as surface roughness, contact area, relative humidity, and SFE of functionalized tips was considered. Two different mathematical approaches based on Johnson-Kendall-Roberts theory were used to calculate SFE from adhesion values. The measured adhesion values showed variations depending on functionalized tip and chocolate gloss area. The results showed a difference in adhesion and, consequently, SFE in the different gloss areas with gloss > homogenous > matt. However, SFE obtained from adhesion forces were not decisive enough to enable a direct correlation with SFE data from contact angle measurements at the same area.
AB - Surface free energy (SFE) is an important surface property in food processing as it determines the wettability of solid surfaces or the interaction of mould surfaces and chocolate during the moulding process. High-resolution information about SFE could be useful to understand gloss inhomogeneities of chocolates after de-moulding. SFE is connected with adhesion properties. Thus, Atomic force microscopy (AFM) adhesion measurements can be applied to determine SFE of a solid surface at microscopic scale. For this purpose, AFM tips were functionalized to modify their SFE and used for adhesion measurements at three different chocolate gloss areas (matt, glossy and homogenous) via AFM force maps. Influence of relevant parameters such as surface roughness, contact area, relative humidity, and SFE of functionalized tips was considered. Two different mathematical approaches based on Johnson-Kendall-Roberts theory were used to calculate SFE from adhesion values. The measured adhesion values showed variations depending on functionalized tip and chocolate gloss area. The results showed a difference in adhesion and, consequently, SFE in the different gloss areas with gloss > homogenous > matt. However, SFE obtained from adhesion forces were not decisive enough to enable a direct correlation with SFE data from contact angle measurements at the same area.
KW - Adhesion
KW - Atomic force microscopy, Surface free energy
KW - Chocolate gloss inhomogemeities
KW - Functionalized tips
KW - Microscopic scale
KW - Root mean square roughness
UR - http://www.scopus.com/inward/record.url?scp=105002920141&partnerID=8YFLogxK
U2 - 10.1016/j.ultramic.2025.114150
DO - 10.1016/j.ultramic.2025.114150
M3 - Article
AN - SCOPUS:105002920141
VL - 273
JO - ULTRAMICROSCOPY
JF - ULTRAMICROSCOPY
SN - 0304-3991
M1 - 114150
ER -