Nanoplasmonics and surface-enhanced spectroscopy

Influence of the substrate zeta potential on the electrostatic deposition kinetics and its simulations by Monte Carlo method
Malakhovsky P.O., Murausky D.I., Minakov E.A.
1 Research Institute for Physical Chemical Problems of the Belarusian State University. Leningradskaya vul., 14, Minsk-220006, Belarus.
E-mail: pashkamusic@gmail.com

Oriented monolayers of silver nanoplates can serve as substrates for surface-enhanced Raman scattering [1]. Recently, we developed a technique of electrostatic deposition of silver nanoplates onto transparent polycationic films of copolymer containing tertiary amino groups. Fig. 1a shows the kinetic curves of nanoplates deposition on films with variable number of amino groups. 

Figure 1. (a) Experimental, simulated kinetic curves of deposition of nanoplates on films with different fraction of amino groups. (b) Impact of film SZP on surface concentration. (c) Experimental and (d) simulated slopes of the linear regime.
Fig. 1a shows the transition from linear diffusion-limited to adsorption-limited regime occurs at different time depending on substrate. Saturated surface concentrations depend linearly on film surface zeta potential (SZP), measured by spinning disk method, while linear slopes in the first regime are not SZP-dependent (Fig 1b,c). We introduced the principle of the effective exclusion radius of particles in classic random sequential adsorption model, and simulated the kinetic curves via Monte Carlo method (Fig 1a). Assumption SZP~1/rex gave a good approximation both for the kinetic curves and for the trend of the linear slopes (Fig 1d).
1.	Langer, J. et al. Present and Future of Surface-Enhanced Raman Scattering // ACS Nano.-2019.-14, N 1.-P. 28-117.