Controlling silver deposition morphology on aluminum surfaces: Surfactant modify anisotropy of aluminum surface energy

Faced with the challenge of uncontrollable Ag layer deposition morphology during the preparation of silver-coated aluminum particles (Al/Ag). A simple and nontoxic method involving the introduction of surfactants (PEG, PVP, and gelatin (GEL)) to alter the anisotropy of Al surface energy was proposed to achieve control over Ag deposition morphology. Theoretical calculations indicate that PEG undergoes physisorption to Al, while PVP and GEL can alter the surface energy of specific crystal planes by selectively binding to different crystal facets. This action alters the growth habit of Ag on the Al surface and modulates the Ag deposition behavior, these conclusions align with experimental results. Compared with PEG and PVP, the incorporation of GEL was beneficial for the formation of a conformal Ag layer. This can be attributed to GEL preferentially passivating the highest crystal plane Al (110) surface, forming a buffer layer at the solid-liquid interface, leveling out the Ag deposition rate on various crystal planes, and also effectively inhibiting side reactions, in addition to enhancing the wettability of reaction solution. The Al/Ag particle exhibits excellent electrical conductivity (1.03 × 10−6 Ω·cm) and electromagnetic absorption (−32.5 dB, 1.62 GHz), it is suitable for use as a highly conductive electromagnetic shielding material.