Mesoscale modeling and computational simulation studies of the self-assemblyof heterogeneous colloidal systems.

Self-assembly;Simulation;Colloid;Colloidal Crystal;Nanoparticle;Nanoelectronics;Chemical Engineering;Engineering;Chemical Engineering

Teich-McGoldrick, Stephanie LeahZiff, Robert M. ;

University of Michigan

关键词: Self-assembly;    Simulation;    Colloid;    Colloidal Crystal;    Nanoparticle;    Nanoelectronics;    Chemical Engineering;    Engineering;    Chemical Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/78889/teichmcg_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Over the last two decades researchers have advanced the field of colloidal synthesisby developing new synthesis techniques. Colloidal particles are known to self-assembleinto various unique architectures. However, there is still no simple rule relating systemcondition and particle type to achievable self-assembled structures. The goal of this thesiswas to use simulation methods to further develop an understanding of how tailoring interparticleinteractions and system parameters (such as temperature and concentration) leads toself-assembled structures.The applicability of one specific colloidal system - nanotetrapods - for use as nanoelectroniccircuit elements is investigated. The electrical response for MESFET and JFETnanotetrapods was determined through Technology Aided Design Tools, and it was determinedthat nanotetrapods have the potential to be utilized as circuit elements. Monte Carlosimulations provide insight into how proper tuning of particle-particle and particle-substrateinteractions result in the assembly of ordered arrays of electrically gated nanotetrapods.We used lattice energy calculations and normal mode analysis (NMA) to investigatethe thermodynamic and mechanical stability of binary, ionic colloidal crystals with sizeratio 1.0 : 0.8. Based on these methods, theoretical predictions were made regarding thestable crystal structure as a function of potential interaction parameters. We found thenormal mode results are in agreement with lattice energy results, and were compared tomolecular dynamics simulations to determine the capacity for self-assembly. We foundthat not all predicted structures are kinetically accessible. Additionally, we investigated theself-assembly of colloidal crystals for one specific interaction parameter as a function ofdensity and temperature, and found that, in addition to the theoretically predicted crystalstructure, a second entropically stabilized crystal structure formed at higher temperatures.The extension of NMA to finite temperature systems was developed without having tocouple to slower simulations. Using the Lennard-Jones model, kinetic energy was introducedinto the system by randomly displacing particles in a crystal. Temperature was related tothese displacements through the equipartition theorem. Upon comparison with publishedwork on the Lennard-Jones spinodal, we determined that NMA reasonably predicts the limitof mechanical stability at low temperatures, but overestimates it at higher temperatures.