Molecular self-assembly at surfaces offers an efficient route to highly-ordered organic films that can be programmed for a variety of applications. However, the success of these materials depends on the ability to program intermolecular interactions that determine ordering at the surface. We study three systems: alkoxybenzonitriles (ABNs), tricarbazolo triazolophane macrocycles (tricarb), and triazolobenzene oligomers in flexible or macrocycle forms. For each model system, experiments employ a range of molecules in which aspects of molecular structure, especially symmetry and peripheral functionalization, are systematically varied to study the impact of intermolecular interactions on 2D supramolecular structure and to gain a deeper understanding of fundamental assembly mechanisms. The supramolecular assemblies are studied by scanning tunneling microscopy (STM) and molecular dynamic (MD) simulations at the solution/graphite interface. Variations in assembly conditions, including solvent, concentration, and temperature, also provide insight into assembly. ABNs exhibit competitive assembly with solvent that can be controlled with alkyl length. MD simulations on nanosecond timescales provide insight into ABN desorption, re-adsorption, and on-surface processes, and simulations reveal an asymmetry in desorption pathways. Triazolobenzene oligomers can be tuned between tight and loose packing of aromatic cores, the latter being separated by lamellar rows of alkanes. Flexible frameworks assemble more slowly compared to macrocycles due to a large conformational space, but self-assembly can be accelerated by co-solutes and STM perturbation. Tricarb exhibits polymorphism, and tricarb-tricarb hydrogen bonding can be controlled by varying the length and symmetry of peripheral alkanes into various structures including a high-density disordered packing. Variable solvent and peripheral group studies indicate that transitions from disordered to ordered structures involve a solution-mediated annealing pathway. MD simulations reveal solvent insertion between tricarb leading to disordered structures, but these can be sterically blocked by longer alkanes. The discoveries presented in this thesis provide insights into the dynamics and design rules of self-assembly.

Self-Assembly Processes at Interfaces: Multiscale Phenomena provides the conceptual and unifying view of adsorption, self-assembly, and grafting processes at solid–liquid and liquid–gas interfaces, also describing experimental methods where applicable. An invaluable resource for (post)-graduate students looking to bridge the gap between acquiring the field’s existing knowledge and the creation of new insights, the book recalls fundamental concepts, giving rigorous, but first-principle-based, calculations and exercises, and showing how these concepts have been used in recent research articles. Readers will find guidelines on how best to start research in the field of surface chemistry with biological macromolecules and molecules able to undergo self-assembly process at interfaces in the presence of a liquid, along with discussions on the very fundamental aspects and applications using concepts of biomimetic chemistry. By highlighting the interdisciplinary aspects of the field of self-assembly at interfaces, the book is an ideal resource for chemical engineers, chemists, physicists, and biologists. In addition, important equations are demonstrated on the basis of fundamental concepts, and overly complex mathematical developments are avoided. Presents an interdisciplinary work that is ideal for chemical engineers, chemists, physicists, and biologists Provides a unifying view of the field, from fundamentals, to methods and applications Includes concepts applicable at both solid–liquid and liquid–gas interfaces

A comprehensive investigation on the formation dynamics and energetics of adlayer formation at the at the solution/solid interface has been performed using scanning tunneling microscopy (STM) with a custom solution flow cell design that offers new insight into the self-assembly process. Understanding the formation kinetics and thermodynamics of self-assembled monolayers (SAM) provides insight into the delicate balance of intermolecular forces on the molecular scale. We herein investigate the growth, dynamics, and stability of a model non-covalent self-assembler -- Co(II) octaethylporphyrin at the solution/solution interface on the HOPG and Au(111) surfaces. Real-time imaging of the nucleation and growth of the self-assembled layer was captured and studied by in-situ STM, and further explored using computational methods. A custom STM solution flow cell was designed and implemented to allow for in-situ monitoring of self-assembly at very low concentrations and with volatile solvents. Flow studies at low concentration provide insight into early-stage kinetics and structural formation of a SAM. It was found that the choice of organic solvent plays a dramatic role in the kinetics and structure of the SAM. These results, in turn, provide insight into the balance of the intermolecular forces driving the self-assembly. The role of the solvent was particularly strong in the case of 1,2,4-trichlorobenzene (TCB) on both HOPG and Au(111). Under TCB, a very stable rectangular structure is formed and stabilized by solvent-incorporation. A transition to a solvent free pseudo-hexagonal structure was only observed when extremely high concentrations of porphyrin were present in solution. Similarly, in the case of CoOEP adsorbed on Au(111) under toluene, a solvent-incorporated rectangular structure was observed that, like the TCB case, transitioned into a pseudo-hexagonal structure, but this transition occurred at much lower concentrations of porphyrin. Toluene co-adsorption was not observed on HOPG. When deposited from decane, a short-lived pseudo-rectangular structure was observed on Au(111) but not on HOPG. Only the pseudo-hexagonal structure was observed in the porphyrin adlayer when 1-phenyloctane were used as a solvent. On HOPG, mixed solvent competition was tested and gave further insight into the thermodynamic and kinetic roles that solvents play in self-assembly.

This book describes techniques of synthesis and self-assembly of macromolecules for developing new materials and improving functionality of existing ones. Because self-assembly emulates how nature creates complex systems, they likely have the best chance at succeeding in real-world biomedical applications. • Employs synthetic chemistry, physical chemistry, and materials science principles and techniques • Emphasizes self-assembly in solutions (particularly, aqueous solutions) and at solid-liquid interfaces • Describes polymer assembly driven by multitude interactions, including solvophobic, electrostatic, and obligatory co-assembly • Illustrates assembly of bio-hybrid macromolecules and applications in biomedical engineering

Liquid-liquid interfaces serve as ideal 2-D templates on which solid particles can self-assemble into various structures. These self-assembly processes are important in fabrication of micron-sized devices and emulsion formulation. At oil/water interfaces, these structures can range from close-packed aggregates to ordered lattices. By incorporating an ionic liquid (IL) at the interface, new self-assembly phenomena emerge. ILs are ionic compounds that are liquid at room temperature (essentially molten salts at ambient conditions) that have remarkable properties such as negligible volatility and high chemical stability and can be optimized for nearly any application. The nature of IL-fluid interfaces has not yet been studied in depth. Consequently, the corresponding self-assembly phenomena have not yet been explored. We demonstrate how the unique molecular nature of ILs allows for new self-assembly phenomena to take place at their interfaces. These phenomena include droplet bridging (the self-assembly of both particles and emulsion droplets), spontaneous particle transport through the liquid-liquid interface, and various gelation behaviors. In droplet bridging, self-assembled monolayers of particles effectively "glue" emulsion droplets to one another, allowing the droplets to self-assembly into large networks. With particle transport, it is experimentally demonstrated the ILs overcome the strong adhesive nature of the liquid-liquid interface and extract solid particles from the bulk phase without the aid of external forces. These phenomena are quantified and corresponding mechanisms are proposed. The experimental investigations are supported by molecular dynamics (MD) simulations, which allow for a molecular view of the self-assembly process. In particular, we show that particle self-assembly depends primarily on the surface chemistry of the particles and the non-IL fluid at the interface. Free energy calculations show that the attractive forces between nanoparticles and the liquid-liquid interface are unusually long-ranged, due to capillary waves. Furthermore, IL cations can exhibit molecular ordering at the IL-oil interface, resulting in a slight residual charge at this interface. We also explore the transient IL-IL interface, revealing molecular interactions responsible for the unusually slow mixing dynamics between two ILs. This dissertation, therefore, contributes to both experimental and theoretical understanding of particle self-assembly at IL based interfaces.

Self-assembly monolayer (SAM) structures of lipids and macromolecules have been found to play an important role in many industrial and biological phenomena. This book describes two procedures, namely the STM and AFM, that are used to study SAMs at solid surfaces. K.S. Birdi examines the SAMs at both liquid and solid surfaces by using the Langmuir monolayer method. This book is intended for researchers, academics and professionals.

In the past several decades, molecular self-assembly has emerged as one of the main themes in chemistry, biology, and materials science. This book compiles and details cutting-edge research in molecular assemblies ranging from self-organized peptide nanostructures and DNA-chromophore foldamers to supramolecular systems and metal-directed assemblies, even to nanocrystal superparticles and self-assembled microdevices