Synthesis and Characterization of Polymeric Materials Derived From Multifunctional Alkyl a-Hydroxymethylacrylates

The research presented in this dissertation covers the investigation of new materials derived from alkyl a-hydroxymethylacrylates (RHMA). The first project exposed in Chapter II involves the synthesis, characterization of RHMA-based reactive surfactants and their successful incorporation in acrylic latexes. The amphiphilic monomers testify of a good copolymerization behavior with other acrylic monomers such as methyl methacrylate and butyl acrylate although their extensive bulkiness. They led to the formation of well-defined polymeric particles via a seeded emulsion polymerization process and permitted decreasing significantly the water sensitivity of the resulting films as compared to film incorporating conventional emulsifier such as sodium dodecyl sulfate. The research presented in Chapter III focuses of the use of such reactive surfactant as compatibilizer in polymer/Ti02 nanocomposites. Their incorporation led to an increase in the overall UV-absorption properties of the resulting polymeric materials correlated by an enhancement of filler dispersion within the matrix. The synthesis, characterization of RHMA-based cationic surfmers is discussed in Chapter IV. Their incorporation in poly(methyl methacrylate)/clay nanocomposites as compatibilizers is studied and the impact of the polymerization technique and of the film formation method used on the composite\u27s properties investigated. Emulsion polymerization led to enhanced filler dispersion when a solvent-casting method was used to form the corresponding film. Chapter V describes the synthesis and polymerization of alkyl 2-carboethoxyhydroxymethylacrylates. Such alkenes display interesting reactivity in radical polymerization compared to other hindered RHMA analogs however, the resulting homo- and copolymers still testify of low yields and molecular weights. This behavior is attributed to some degree of chain transfer to monomer that may involve the allylic proton. Chapter VI presents the synthesis of polyfunctional 2-pyrrolidinone derivatives from a variety of new alkyl 2-carboethoxyhydroxymethylacrylates via a very efficient Michael addition/cyclization reaction sequence. Fast, clean, quantitative, and leading to compounds with no need for subsequent purification, this click reaction opens up a brand new synthetic window to the preparation of new optically active derivatives. The preparation of new 2-pyrrolidinone acid derivatives is described in Chapter VII. The separation of the cis and trans isomers composing the resulting product were successfully separated by simple recrystallization technique. The study of hydrogen bonding interactions intrinsic of such heterocycle allowed confirming the respective isomer structures. The synthesis and photopolymerization kinetics of new pyrrolidinone methacrylate monomers are described in Chapter VIII as well as the characterization of the corresponding homopolymers. The importance of hydrogen-bonding interactions in the polymerization kinetics as well as on the final polymer properties are discussed. Responsible for enhancing the polymerization rate of the pyrrolidinone-containing monomers prepared, hydrogen-bonding interactions led to the apparition of a pseudo beta transition for the resulting homopolymers. Chapter IX involves the synthesis of bis-pyrrolidinone acid derivatives. It was found that such derivatives display Tgs during thermal analysis. This polymer-like behavior is attributed to non-covalent supramolecular associations. The final part of this dissertation involves the kinetics study of the Michael addition/cyclization reaction sequence and polymerization involving alkyl 2-carboethoxyhydroxymethylacrylates and primary amines. This new polymerization route led to the formation of a new class of poly(ester amide)s with potential applications as biodegradable coatings

Programmable Multimode Quantum Networks

Entanglement between large numbers of quantum modes is the quintessential resource for future technologies such as the quantum internet. Conventionally the generation of multimode entanglement in optics requires complex layouts of beam-splitters and phase shifters in order to transform the input modes in to entangled modes. These networks need substantial modification for every new set of entangled modes to be generated. Here we report on the highly versatile and efficient generation of various multimode entangled states with the ability to switch between different linear optics networks in real time. By defining our modes to be combinations of different spatial regions of one beam, we may use just one pair of multi-pixel detectors each with M photodiodes in order to measure N entangled modes, with a maximum number of N=M modes. We program virtual networks that are fully equivalent to the physical linear optics networks they are emulating. We present results for N=2 up to N=8 entangled modes here, including N=2,3,4 cluster states. Our approach introduces flexibility and scalability to multimode entanglement, two important attributes that are highly sought after in state of the art devices.Comment: 10 pages, 5 figures, 2 tables, comments welcome

Impurity conduction in phosphorus-doped buried-channel silicon-on-insulator field-effect transistors

We investigate transport in phosphorus-doped buried-channel metal-oxide-semiconductor field-effect transistors at temperatures between 10 and 295 K. In a range of doping concentration between around 2.1 and 8.7 x 1017 cm-3, we find that a clear peak emerges in the conductance versus gate-voltage curves at low temperature. In addition, temperature dependence measurements reveal that the conductance obeys a variable-range-hopping law up to an unexpectedly high temperature of over 100 K. The symmetric dual-gate configuration of the silicon-on-insulator we use allows us to fully characterize the vertical-bias dependence of the conductance. Comparison to computer simulation of the phosphorus impurity band depth-profile reveals how the spatial variation of the impurity-band energy determines the hopping conduction in transistor structures. We conclude that the emergence of the conductance peak and the high-temperature variable-range hopping originate from the band bending and its change by the gate bias. Moreover, the peak structure is found to be strongly related to the density of states (DOS) of the phosphorus impurity band, suggesting the possibility of performing a novel spectroscopy for the DOS of phosphorus, the dopant of paramount importance in Si technology, through transport experiments.Comment: 9 figure

Quantum protocols with transverse spatial modes

We present in this thesis a study of the spatial properties of light at the quantum level. More specifically, we focus on techniques to manipulate the quantum fluctuations of different degrees of freedom in a beam's transverse plane, and on the quantum protocols we can implement using these specific fluctuations. We begin by providing an experimental characterization of different methods to manipulate the quantum fluctuations of multiple transverse profiles, or modes, in one beam. While manipulating the quantum fluctuations of a mode, a process known as squeezing, for a single mode beam can be performed very efficiently using a conventional optical parametric oscillator, we present implementations of different, less conventional techniques able to generate a beam carrying multiple squeezed modes. Conventionally, the squeezed modes we can generate using these techniques are fixed by the optical design. We present a new optical system, called a Unitary Programmable Mode Converter (UPMC), able to reshape these modes at will. We show theoretically that such a UPMC can in principle perform any desired reshaping of the modes. We present the performances of an experimental implementation of the UPMC, both in a classical and quantum context. We find that the UPMC performs as predicted, and we present a method to optimize the UPMC settings taking into account experimental restrictions. The UPMC, combined with a technique to build a beam carrying multiple squeezed modes, allows us to generate a beam with squeezing in any desired set of spatial modes. In order to detect these fluctuations, we built a multipixel homodyne detection, a detection system able to record simultaneously the quantum fluctuations in all these modes. We provide in this thesis our solutions to overcome the electronic challenges associated with such a device, and present an experimental characterization of the performances of our multipixel homodyne detection. Finally, we combine these experimental characterizations to discuss how these techniques help us implement different quantum protocols involving multiple spatial modes, more specifically quantum enhanced detections and cluster states quantum computation

Synthesis of New Hydroxylated Monomers Based on Methacrylate, Dimethacrylate, and Tetramethacrylate Michael and Photopolymerization Kinetics of Bulk Cross-Linkers

A series of new hydroxylated monomers was synthesized from the Michael addition reaction between ethanolamine, diethylene glycol amine, triethylene glycol amine, tetradecylamine, and adamantanamine with 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM). Selective formation of secondary amine (mono adduct) or tertiary amine (his adduct) products was obtained by controlling the stoichiometry of the reactants and reaction temperature. The Michael addition reactions were highly exothermic and carried out without the need of catalyst. The use of solvent, however, was required in some systems. The tetramethaerylate monomer was synthesized via the Michael addition reaction of 1,6-hexanediamine (HDA) to AHM. The photopolymerization kinetics of the synthesized monomers were investigated using differential scanning calorimeter. The rates of polymerization for the hydroxylated dimethacrylate systems were significantly higher than that of a typical dimethacrylate monomer (HDDMA) and approached that of the diacrylate HDDA, with overall conversions ranging from 80 to 87%

Spatial reshaping of a squeezed state of light

Reshaping the spatial profile, or mode, of a quantum state of light is one of the challenges in many quantum optics applications. We test the noise properties of a universal programmable mode converter and demonstrate that it can reshape the spatial mod

Asymmetric EPR entanglement in continuous variable systems

Continuous variable entanglement can be produced in nonlinear systems or via the interference of squeezed states. In many optical systems such as parametric down conversion, the production of two perfectly symmetric subsystems is usually assumed when demonstrating the existence of entanglement. This symmetry simplifies the description of entanglement. However, asymmetry in entanglement may arise naturally in a real experiment, or be intentionally introduced in a given quantum information protocol. These asymmetries can emerge from having the output beams experience different losses and environmental contamination, or from the availability of non-identical input quantum states in quantum communication protocols. In this paper, we present a visualization of entanglement using quadrature amplitude plots of the twin beams. We quantitatively discuss the strength of asymmetric entanglement using EPR and inseparability criteria and theoretically show that the optimal beamsplitter ratio for entanglement is dependent on the asymmetries and may not be 50 : 50. To support this theory, we present experimental results showing one particular asymmetric entanglement where a 78 : 22 beamsplitter is optimal for observing entanglement

Reconfigurable multi-mode entanglement within one beam

New continuous variable quantum protocols such as cluster state computation [1] and quantum error correction [2] require an increasing number of modes to be entangled in a specific way. Conventionally, the entangled modes are carried by as many single mode beams [3, 4]. In order to produce entanglement, each beam of classical light first goes through a single mode optical parametric amplifier (OPA). This OPA reduces the variance of one of the quadratures of one mode of the electromagnetic field below the quantum noise limit (the mode is then called squeezed). The squeezed modes are then mixed together using a specific sequence of beam-splitters of defined ratios. For each beamsplitter, the relative phase of the two input modes is also defined and controlled. To each sequence of beam-splitting ratios and relative phases corresponds a unitary transformation between the input modes and the output modes. This unitary transformation gives a set of sub quantum noise relationships between the output modes quadratures with each protocol defined by a different set of relationships. After the desired entanglement has been produced, homodyne detections are performed on the output modes to implement the protocol. Using one beam per mode is resource heavy and inflexible. We present and characterize an alternative set of tools for flexible, computer reconfigurable, multi-mode entanglement