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Surfaces and Interfaces of Liquid Metal Core–Shell Nanoparticles under the Microscope
Author(s) -
Hafiz Sabrina S.,
Labadini Daniela,
Riddell Ryan,
Wolff Erich P.,
Xavierselvan Marvin,
Huttunen Paul K.,
Mallidi Srivalleesha,
Foster Michelle
Publication year - 2020
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.201900469
Subject(s) - eutectic system , alkyl , nanoparticle , materials science , ligand (biochemistry) , nanotechnology , carboxylate , gallium , alloy , chemical engineering , chemistry , chemical physics , organic chemistry , composite material , metallurgy , biochemistry , receptor , engineering
Abstract Eutectic gallium indium (EGaIn), a Ga‐based liquid metal alloy holds great promise for designing next‐generation core–shell nanoparticles (CSNs). A shearing‐assisted ligand‐stabilization method has shown promise as a synthetic method for these CSNs; however, determining the role of the ligand on stabilization demands an understanding of the surface chemistry of the ligand–nanoparticle interface. EGaIn CSNs are created and functionalized with aliphatic carboxylates of different chain length, allowing a fundamental investigation on ligand stabilization of EGaIn CSNs. Raman and diffuse reflectance Fourier transform spectroscopies (DRIFTS) confirm reaction of the ligand with the oxide shell of the EGaIn nanoparticles. Changing the length of the alkyl chain in the aliphatic carboxylates (C2–C18) may influence the size and structural stability of EGaIn CSNs, which is easily monitored using atomic force microscopy (AFM). No matter how large the carboxylate ligand, there is no obvious effect on the size of the EGaIn CSNs, except the particle size getting more uniform when coated with longer chain carboxylates. The AFM force–distance measurements are used to measure the stiffness of the carboxylate‐coated EGaIn CSNs. In corroboration with DRIFTS analysis, the stiffness studies show that the alkyl chains undergo conformational changes upon compression.