Thermal and morphological studies of the segmented multiblock copolyesters containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol and dimethyl-1,4-cyclohexane dicarboxylate were carried out using differential scanning calorimetry, small angle X-ray scattering, wide angle X-ray diffraction and dynamic mechanical analysis. Molecular origins of the thermal transitions appearing in copolyesters were assigned by the copolyester analysis at different temperatures. The hard segments in copolyesters underwent short-range and long-range ordering (crystallization) during cooling or annealing above glass transition temperature, as concluded from thermal and wide angle X-ray diffraction analysis. Annealing process affected the ordering in hard segments and annealing temperatures of 160 °C and above led to increased microphase mixing. The small angle X-ray scattering studies confirmed the microphase separated morphology of copolyesters and supported the argument of increased microphase mixing in copolyesters annealed at higher temperatures. The amount of sulfonate containing co-monomer and its presence in either hard or soft microphase affected the morphology of the copolyesters. Introduction of the sulfonate groups led to increased microphase mixing in copolyesters as well as destruction of long-range order in the hard segments. / Master of Science

Yes / AB and ABA di- and triblock copolymers where A is the hydrophilic poly(oligoethylene glycol methacrylate) (POEGMA) block and B is a thermo-responsive sulfobetaine block [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (PDMAPS) were synthesised by aqueous RAFT polymerisation with narrow dispersity (ĐM ≤ 1.22), as judged by aqueous SEC analysis. The di- and triblock copolymers self-assembled in salt-free water to form micelles with a PDMAPS core and the self-assembly of these polymers was explored by SLS and TEM analysis. The micelles were shown, by DLS analysis, to undergo a micelle-to-unimer transition at a critical temperature, which was dependent upon the length of the POEGMA block. Increasing the length of the third, POEGMA, block decreased the temperature at which the micelle-to-unimer transition occurred as a result of the increased hydrophilicity of the polymer. The dissociation of the micelles was further studied by SLS and synchrotron SAXS. SAXS analysis revealed that the micelle dissociation began at temperatures below that indicated by DLS analysis and that both micelles and unimers coexist. This highlights the importance of using multiple complementary techniques in the analysis of self-assembled structures. In addition the micelle-to-unimer morphology transition was employed to encapsulate and release a hydrophobic dye, Nile Red, as shown by fluorescence spectroscopy. / Engineering and Physical Sciences Research Council (EPSRC), University of Warwick

Yes / The synthesis and self-assembly of thymine-containing polymers were performed using RAFT dispersion polymerization. A combination of microscopy and scattering techniques was used to analyze the resultant complex morphologies. The primary observation from this study is that the obtained aggregates induced during the polymerization were well-defined despite the constituent copolymers possessing broad dispersities. Moreover, a variety of parameters, including the choice of polymerization solvent, the degree of polymerization of both blocks and the presence of an adenine-containing mediator, were observed to affect the resultant size and shape of the assembly. / University of Warwick, National Science Foundation (U.S.) (NSF), Engineering and Physical Sciences Research Council (EPSRC)

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Alloy nanoparticles have been extensively studied for decades. However, the synthesis and characterization of alloy nanoparticles are still posing significant challenges, leading to an increasing demand for in situ characterization techniques. Small-angle X-ray scattering (SAXS) is a powerful method for structural analysis of nanoparticles. As the SAXS signal is essentially the Fourier transform of the electron distribution, it provides structural information for the entire ensemble of nanoparticles. The development of SAXS has been facilitated by significant advances in synchrotron X-ray sources and data processing methods, leading to the development of the 3D-SAXS method, which enables the reconstruction of the 3D structures of particles from SAXS profiles.Although SAXS has the potential to be a powerful tool for investigating the internal structures of alloy nanoparticles, its application is hindered by the challenges posed by polydispersity, which can cause smearing effects that complicate the geometry recovery process. This dissertation presents a novel approach to overcome the problem of polydispersity in SAXS data analysis, thus demonstrating the utility of SAXS in investigating the internal electron density distributions of alloy nanoparticles. In Chapter 2, the SharPy algorithm is introduced as a size-refocusing program that reduces the smearing effect caused by polydispersity in SAXS data. SharPy is based on a penalized iterative regression approach to fit the pair distance distribution function (PDDF) with an estimated size distribution. It can provide detailed information about the shape of nanoparticles from the smeared SAXS signal under various scenarios and conditions. Chapter 3 investigates the simulated SAXS profiles of AuAg core-shell nanoparticles with varying size distribution, core-shell ratio, and degrees of alloying. It demonstrates the capability of SAXS in observing the electron density distribution of AuAg core-shell structures. These findings provide insights into the potential of SAXS as a reliable method for investigating the internal structures of alloy nanoparticles. Chapter 4 focuses on synthesizing and characterizing AuAg nanoparticles. Their SAXS profiles and PDDF analysis demonstrate that SAXS can distinguish between homogeneous and core-shell nanoparticle structures. In this chapter, the SharPy algorithm is first-time applied to real experimental data, demonstrating its ability to reveal the core-shell structure from a polydisperse nanoparticle system. Chapter 5 investigates the evolution of alloying AuAg nanoparticles through a combination of SAXS/PDDF analysis, 3D reconstruction, and molecular dynamics (MD) simulation. The study presents the 3D electron density distribution of alloying AuAg nanoparticles. The 3D reconstruction with electron density mapping provides a straightforward visualization of the electron density distribution pattern of the alloying AuAg nanoparticles. The success of the SAXS experiment lies in the development of the 3D-SAXS pipeline, which involves the use of SharPy and 3D reconstruction programs, making 3D SAXS a promising alternative to electron microscopy for visualizing the morphology of nanoparticle systems. / Chemistry

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京都大学 / 新制・課程博士 / 博士(工学) / 甲第23922号 / 工博第5009号 / 新制||工||1782(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 竹中 幹人, 教授 古賀 毅, 教授 中村 洋 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM