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Formation of gold nanoparticle bilayers on gold sensors

Author:
Maciejewska-Prończuk, J., Oćwieja, M., Adamczyk, Z., Pomorska, A.
Source:
Colloids and surfaces 2019 v.560 pp. 393-401
ISSN:
0927-7757
Subject:
adsorption, atomic force microscopy, chemical reduction, colloids, electrophoresis, electrostatic interactions, gold, ionic strength, models, nanogold, nanoparticles, pH, quartz, scanning electron microscopy, transmission electron microscopy
Abstract:
Formation of bilayers composed from oppositely charged gold nanoparticles and characterized by comparable size distribution was investigated using gravimetric and microscopic techniques. Positively (AuNPsCH(+)) and negatively charged (AuNPsTC(−)) gold nanoparticles were synthesized according to chemical reduction procedure. The transmission electron microscopy (TEM) revealed that the nanoparticle size was equal to 9.0 ± 3 nm and 14 ± 2 nm in the case of AuNPsCH(+) and AuNPsTC(−), respectively. The electrophoretic mobility measurements allowed to determine the electrokinetic properties of the nanoparticles and their stability under various conditions of pH and ionic strengths. Both the deposition kinetics of AuNPsCH(+) on gold sensors and the formation kinetics of second AuNPsTC(−) layer were determined using quartz microbalance (QCM) measurements. Additionally, the maximum coverage and bilayer structure were evaluated using atomic force microscopy (AFM) and scanning electron microscopy (SEM). In these measurements a negligible hydratation of AuNPsCH(+)/AuNPsTC(−) bilayers was confirmed. The significant increase in the maximum coverage of both supporting and external layers with ionic strength was interpreted as a results of decreasing range of repulsive electrostatic interactions among deposited nanoparticles. The experimental results were quantitatively interpreted in terms of the extended random sequential adsorption (eRSA) model.
Agid:
6180129