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Thesis advisor: Jeffery A. Byers / This dissertation discusses the development of catalytic systems within the context of polymer synthesis and functionalization towards the fulfillment of circular plastic economy. Chapter 1 provides an overview of the limitations of the current mechanical recycling for plastic disposal and two general ways to improve the current system by chemical strategies. Chapter 2 discusses the development of a chemically recyclable thermoplastic elastomer derived from relatively cheap feedstock using redox-switchable polymerization. Chapter 3 describes the application of C-H activation and cross-coupling strategy on commodity polyolefins and the effect on the polymer physiochemical properties by the introduction of functional groups, which has the potential to serve in polymer upcycling. Chapter 4 describes the dehydrogenation of polyethylene (PE) and polypropylene (PP) along with further functionalization of the unsaturated product to demonstrate a route of synthesizing PE/PP compatibilizers from plastic waste. Chapter 5 summarizes our development of simulation-based methods to obtain kinetic information of transition-metal catalyzed copolymerization that may include reversible propagation. / Thesis (PhD) — Boston College, 2024. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

This work seeks to develop new solvents for environmentally benign chemical synthesis. Switchable solvents are a new class of compounds that change properties upon the application of some stimulus such as heat, UV light, or pH. We have developed the use of a new solvent, thiirane oxide, that has chemical properties similar to DMSO. Thiirane oxide, however, undergoes facile decomposition to two gases at temperatures above 100 C, which is much lower than the temperature required for removing DMSO. Thus we have a solvent with excellent solvation properties, but with a built-in switch for easier removal. However, thiirane oxide leaves behind sulfurous products which make the reverse reaction to reform the solvent unfeasible. We are also developing the use of another solvent, piperylene sulfone, which is expected to have good solvent properties, yet with decomposition products that can be reacted to reform the solvent. This thesis also details the work to date on piperylene sulfone. Gas-expanded liquids (GXLs) also show promise as a new reaction medium. In order to design solvent systems that take full advantage of this medium, we desire to understand the microstructure of these fluids. To that end, we are using cage reactions to probe solute-solvent and solvent-solvent interactions at the molecular level. This thesis discusses the current research on using cage reactions to probe the structure of GXLs.

The work in this thesis couples reactions with separations through the use of switchable and tunable solvents. Tunable solvents are mixed solvents which can be easily altered to afford conditions optimal for reaction or separation. Switchable solvents are solvents that can be switched when desired to alter their properties affording conditions suitable for separation. Other studies are of the reaction of CO2 with the amidine base DBU, and an NMR study of solvent-to-solute nuclear Overhauser effects. These examples constitute a marriage of reaction environment with separation environment, significantly, to the benefit of both.

Today, the advances in Complementary MetalOxideSemiconductor (CMOS) technology have guided the progress in the wireless communications circuits and systems area. Various new communication standards have been developed to accommodate a variety of applications at different frequency bands, such as cellular communications at 900 and 1800 MHz, global positioning system (GPS) at 1.2 and 1.5 GHz, and Bluetooth andWiFi at 2.4 and 5.2 GHz, respectively. The modern wireless technology is now motivated by the global trend of developing multi-band/multistandard terminals for low-cost and multifunction transceivers. Exploring the unused 10-66 GHz frequency spectrum for high data rate communication is also another trend in the wireless industry. In this dissertation, the challenges and solutions for designing a multi-band/multistandard mobile device is addressed from system-level analysis to circuit implementation. A systematic system-level design methodology for block-level budgeting is proposed. The system-level design methodology focuses on minimizing the power consumption of the overall receiver. Then, a novel millimeter-wave dual-band receiver front-end architecture is developed to operate at 24 and 31 GHz. The receiver relies on a newly introduced concept of harmonic selection that helps to reduce the complexity of the dual-band receiver. Wideband circuit techniques for millimeterwave frequencies are also investigated and new bandwidth extension techniques are proposed for the dual-band 24/31 GHz receiver. These new techniques are applied for the low noise amplifier and millimeter-wave mixer resulting in the widest reported operating bandwidth in K-band, while consuming less power consumption. Additionally, various receiver building blocks, such as a low noise amplifier with reconfigurable input matching network for multi-band receivers, and a low drop-out regulator with high power supply rejection are analyzed and proposed. The low noise amplifier presents the first one with continuously reconfigurable input matching network, while achieving a noise figure comparable to the wideband techniques. The low drop-out regulator presented the first one with high power supply rejection in the mega-hertz frequency range. All the proposed building blocks and architecture in this dissertation are implemented using the existing silicon-based technologies, and resulted in several publications in IEEE Journals and Conferences.

A novel strategy for fabrication of responsive functional polymer films is based on grafting of several different functional polymers onto a solid substrate at high grafting density, resulting in varied types of polymer brushes. Such an arrangement suggests many interesting applications of the multicomponent polymer brushes, regarding their versatile adaptive surfaces, capable for responding to changes of solvent polarity, pH, temperature, electromagnetic field and other stimuli, generally by reversible swelling. Mixed amphiphilic polystyrene-poly(2-vynil pyridine) (PS-P2VP) brushes are an example for responsive class of smart materials, which can switch between hydrophilic and hydrophobic energetic state upon changes in the quality of surrounding media. The switching of wettability was found to operate in a broad range and was selectively controlled in organic solvents and in aqueous solutions. Another example for an adaptive/switching behavior is addressed to a polymer brush with a remarkable response to the pH and the ionic strength variations of the aqueous solutions. Combination of weak polyacrylic acid, PAA, and weak polybase, P2VP, in the anchored layer allowed one with a small shift of the pH, to obtain a significant effect on the surface and the interfacial properties of the material. Both type of polymer brushes were examined as adsorbing materials for nanoparticles and charged synthetic- and bio-macromolecules. Their adaptive properties were successively linked to the results of the adsorption experiments. The simplest case was adsorption of nano-particles, functionalised with strong ionic groups, onto binary, PAA-P2VP, polyelectrolyte brushes. Maintaining a constant charge density of the adsorbing component (strong polyelectrolyte effect), allowed one to cause and manipulate a privileged swelling of one of the weak polyelectrolyte brush layers, without affecting the adsorbate properties, and to regulate the thickness of adsorbed layer only by the pH signal. In the case of adsorption of macromolecules with tuneable electrical charge (polyampholytes and proteins), the system became more complicated, regarding their environmentally responsive properties, similar to that exhibited by the polymer brushes. The driving forces were regulated by the switching performance of the brush, simply by adjusting the pH and/or ionic strength conditions. The adsorbed amount and morphological changes of polyampholyte layers were investigated as function of pH and was performed on mixed amphiphilic and binary polyelectrolyte brushes. A special emphasis was set on the binary brush capability to take the control over the interfacial performance of attaching proteins. It was found, that the sharp environmental response of the adsorbent (the polymer brush) strongly influences the morphology of adsorbed protein layers, their thickness and properties. Changing the polarity of the substrate allowed one to regulate the adsorption processes qualitatively and quantitatively. The significant aggregation of protein molecules on PS-P2VP brush and their disassembly on PAA-P2VP brush at the same solvent conditions, we devote to the hydrophobic-hydrophilic transition, occurred at the surface by replacing PS with PAA. The protein aggregates, monitored on the surface of PS-P2VP, sufficiently decrease their size, when switching the brush energetic state from hydrophobic to hydrophilic by adjusting the pH of the media. This effect was found to be well controlled by the brush switching phenomenon in hydrophilic-hydrophobic direction and vice versa. In conclusion, we showed how the structural reorganization in thin polymer brush layers of different type may dramatically affect their surface properties. The adaptive behavior in response of external stimuli was found to be a basis for highly specific interactions, depending on geometric factors, conformational state and environment.

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Pouvoir aller de la molécule aux dispositifs technologiques est un des enjeux actuels dans le domaine des molécules commutables. Dans ce contexte, les complexes à transition de spin (TS) sont de bons candidats car ils peuvent commuter d'un état bas spin vers un état haut spin de manière réversible sous l'influence de stimuli externes (température, lumière...). Il en résulte une modification importante de leurs propriétés physiques (magnétique, optique, élastique etc.). L'objectif de cette thèse est de synthétiser et de caractériser des films et des nanocomposites de matériaux à transition de spin en vue d'applications dans des dispositifs électroniques, mécaniques et optique. Une première approche synthétique pour obtenir des films minces intégrables consiste à utiliser la technique de sublimation. Dans cette optique des complexes neutres du Fe(II) à base de ligand poly(azolyl)borate ont été synthétisés. L'étude de la corrélation de leurs propriétés de TS et des propriétés structurales a été complétée par une étude synchrotron pour déterminer les paramètres de la dynamique du réseau cristallin. Les films de ces complexes ont pu être intégrés dans des jonctions électriques verticales conférant à ces dernières des nouvelles propriétés de bistabilité et illustrant différents mécanismes de conduction en fonction de l'épaisseur du film de complexe. D'autre part ces films ont aussi été déposés sur des dispositifs électromécaniques micrométriques (MEMS) qui ont présenté des propriétés mécaniques bistables. Une autre approche réside dans l'élaboration de matériaux composites constitués de polymère et de complexe à TS. Ainsi, un papier composite de cellulose à base de complexe à TS a été préparé et l'étude par analyse mécanique dynamique a permis de démontrer une bistabilité de ses propriétés mécaniques. Une preuve de concept de papier ré-inscriptible liée au thermochromisme du complexe est également présentée. D'autre part, un nanocomposite à base de polymère électroactif P(VDF-trFE) (piezo-, pyro- et ferroélectrique) et de nanoparticules à TS a été synthétisé. L'étude des propriétés électromécaniques a révélé la présence de pics de décharge de courant associé à la TS indiquant une synergie entre les deux constituants du composite. / Nowadays, going from molecules to devices is one of the main challenge in the field of switchable molecular materials. In this context, spin crossover complexes (SCO) are good candidates as they can be reversibly switched from a low spin state to a high spin state with various external stimuli (temperature, light ...). This switch is followed by an important change of their physical properties (magnetic, optical, elastic...). The objective of this Ph.D thesis is to synthetize and characterize films and nanocomposites based on spin crossover materials for applications in electronical and mechanical and optical devices. A first approach to obtain thin film that can be integrated consist in using sublimation technique. To this aim, neutral Fe(II) complexes based on poly(azolyl)borate ligand have been synthetized. Studies of the correlation between spin crossover properties and structural properties have been complemented with synchrotron measurements to determine crystal lattice dynamics parameters. Films of these complexes have been integrated in electrical junction bringing new bistability properties and displaying different conduction mechanisms depending on the SCO film thickness. Films have been also deposited on micro-electromechanical systems (MEMS) which demonstrated mechanical bistability. Another approach reside in elaborating composite materials based on polymer and SCO complexes. Thus, a cellulose composite paper based on SCO complexes has been prepared and studied by dynamic mechanical analysis indicating a bistability of its mechanical properties. A proof of concept of a re-writable composite paper using SCO thermochromism has been presented. In another hand, nanocomposites based on the electroactive polymer P(VDF-trFE) (piezo-, pyro- and ferroelectric), and SCO nanoparticles has been synthetized. A study of their electromechanical properties revealed current discharge peaks associated to the SCO phenomenon highlighting a synergy between the two composites constituents.

This research aims to develop solutions to relieve system stress conditions in electric grids. The approach adopted in this research is based on a new concept in the Smart Grid, namely, demand response optimization. A number of demand response programs with energy storage systems are designed to enable a community to achieve optimal demand side energy management. The proposed models aim to improve the utilization of the demand side energy through load management programs including peak shaving, load shifting, and valley lling. First, a model is proposed to nd the optimal capacity of the battery energy storage system (BESS) to be installed in a power system. This model also aims to design optimal switchable loads programs for a community. The penetration of the switchable loads versus the size of the BESS is investigated. Another model is developed to design an optimal load operation scheduling of a residential heating ventilation and air-conditioning system (HVACs). This model investigates the ability of HVACs to provide optimal demand response. The model also proposes a comfort/cost trade-os formulation for end users. A third model is proposed to incorporate the uncertainty of the photovoltaic power in a residential model. The model would nd the optimal utilization of the PV-output to supply the residential loads. In the first part of this research, mixed integer programming (MIP) formulations are proposed to obtain the optimal capacity of the (BESS) in a power system. Two optimization problems are investigated: (i) When the BESS is owned by a utility, the operation cost of generators and cost of battery will be minimized. Generator on/o states, dispatch level and battery power dispatch level will be determined for a 24-hour period. (ii) When the BESS is owned by a community for peak shaving, the objective function will have a penalty component for the deviation of the importing power from the scheduled power. MIP problems are formulated and solved by CPLEX.The simulation results present the effect of switchable load penetration level on battery sizing parameters. In the second part, a mixed integer programming (MIP) based operation is proposed in this part for residential HVACs. The objective is to minimize the total cost of the HVAC energy consumption under varying electricity prices. A simplied model of a space cooling system considering thermal dynamics is adopted. The optimization problems consider 24-hour operation of HVAC. Comfort/cost trade-o is modeled by introducing a binary variable. The big-M technique is adopted to obtain linear constraints while considering this binary variable. The MIP problems are solved by CPLEX. Simulation results demonstrate the effectiveness of HVAC's ability to respond to varying electricity price. Then, in the final part of this research, two Benders Decomposition strategies are applied to solve a stochastic mixed integer programming (MIP) formulation to obtain the optimal sizing of a photovoltaic system (PV) and battery energy storage system (BESS) to power a residential HVACs. The uncertainty of PV output is modeled using stochastic scenarios with the probability of their occurrence. Total cost including HVAC energy consumption cost and PV/battery installation cost is to be minimized with the system at grid-connected mode over eight hours subject to a varying electricity price. The optimization problem will nd the optimal battery energy capacity, power limit, a number of PV to be installed, and expected HVAC on/o states and BESS charging/discharging states for the next eight hours. This optimization problem is a large-scale MIP problem with expensive computing cost.

Ce travail décrit la synthèse, les propriétés et la réactivité de cages moléculaires covalentes composées de deux porphyrines, synthétisées avec succès par effet template du DABCO, par CuAAC introduisant des sites périphériques triazoles permettant de contrôler la taille de la cavité grâce à différents stimuli chimiques. Ces cages se composent de porphyrines base libre ou métallées au zinc(II), à l’aluminium(III) ou au cobalt(III). La coordination réversible d’ions Ag(I) ou Cu(I) aux triazoles des cages moléculaires permet de passer d’une conformation aplatie à une conformation ouverte. La protonation des sites basiques permet l’ouverture maximale de la cage. Concernant leur réactivité, les cages aux porphyrines d’Al(III) permettent de catalyser la méthanolyse d’un triester de phosphate. Les cages aux porphyrines de Co(III) catalysent la synthèse de carbonates cycliques à partir d’époxyde et de CO2, sans formation de polycarbonates et avec une conversion totale en présence de pyridine comme co-catalyseur. Les cages bis-porphyriniques ont démontré dans ces réactions, une activité catalytique supérieure à celle des métalloporphyrines de référence. / This work describes the synthesis, properties and reactivity of porphyrinic molecular cages. The successful synthesis of these covalent cages relies on a DABCO-CuAAC templated reaction, which enables to introduce triazole as peripheral binding sites. These cages incorporate either two free base porphyrins or zinc(II), aluminium(III) or cobalt(III) metalloporphyrins. Reversible coordination of Ag(I) or Cu(I) ions to the triazoles of the cages allows to control the cavity size and to switch between a flattened and an opened conformation. Protonation of the basic sites of the cage leads to its maximal expansion. Cages with Al(III) porphyrins have shown to act as catalyst in the phosphate triester methanolysis reaction. Cages with Co(III) porphyrins catalyze the synthesis of cyclic carbonates from CO2 and epoxide without formation of polycarbonate and with total conversion upon addition of pyridine as co-catalyst. In these reactions, the bis-porphyrinic cages have shown to behave as more efficient catalysts than the metalloporphyrin monomers used as reference.