Layer-by-layer assembly of nanorods on a microsphere via electrostatic interactions

Area of Science:

• Materials Science
• Surface Chemistry
• Computational Chemistry

Background:

• Layer-by-layer (LbL) assembly is a versatile technique for creating complex nanostructures.
• Understanding the dynamics and equilibrium of charged nanorods (NRs) on charged microspheres (MS) is crucial for controlled fabrication.

Purpose of the Study:

• To systematically investigate the dynamics and equilibrium behavior of LbL assembly of charged NRs onto charged MS using electrostatic interactions.
• To elucidate the influence of nanorod concentration on adsorption kinetics and multilayer formation.

Main Methods:

• Coarse-grained molecular dynamics simulations were employed to model the assembly process.
• Experimental validation was performed using alpha-Fe2O3 NRs and modified magnetic microspheres.

Main Results:

• First layer NR adsorption exhibited growth-saturation dynamics, with adsorption rate dependent on NR concentration (CNR).
• Equilibrium NR coverage followed a Langmuir adsorption model.
• Multilayer assembly showed linear or quadratic relationships between adsorbed NRs (N) and dip number (M), depending on CNR.

Conclusions:

• The study provides a comprehensive understanding of charged NR LbL assembly on MS.
• Findings offer guidelines for designing superparticles with tailored properties for applications in surface modification, sensors, and drug delivery.