This thesis describes syntheses and characterization of star-like amphiphilic block copolymers consisting of poly(ethylene glycol) (PEG) as the hydrophilic block,polycarbonate as the hydrophobic block and an amine-containing dendrimer as the core molecule. The macromolecules were synthesized by either a convergent or adivergent approach that includes tandem click reactions and ring opening polymerizations (ROP) of methyl trimethyl carbonates (MTC) with differentfunctionalities. The ROP of MTC monomers was performed using organocatalysts that allow mild reaction condition and reasonable molecular weight distribution(PDI~1.3). These synthetic approaches provide the resultant polymers with three different conformations, which are; mikto-arm type, comb-block with short PEGbrushes, and linear block with long PEG chain. The star-like polymers that were synthesized were all water soluble and most of them formed nano aggregates inwater. Different morphologies were observed in AFM study depending on the polymer conformation. Interestingly, some of them had indications pointing towards alower critical solution temperature.

<p>Antivascular targeting is a promising strategy for tumor therapy. This strategy overcomes many of the transport barriers and has shown efficacy in many preclinical models, but targeting epitopes on tumor vasculature can also promote accumulation in healthy tissues. We used Elastin-like Polypeptide (ELP) to form block copolymers (BCs) consisting of two separate ELP blocks seamlessly fused at the genetic level. ELPBCs self-assemble into spherical micelles at a critical micelle temperature (CMT), allowing external control over monovalent unimer and multivalent micelle forms. We hypothesized that thermal self-assembly could trigger specific binding of ligand-ELPBC to target receptors via the multivalency effect as a method to spatially restrict high-avidity interactions. We termed this approach Dynamic Affinity Modulation (DAM). The objectives of this study were to design, identify, and evaluate protein-based drug carriers that specifically bind to target receptors through static or dynamic multivalent ligand presentation.</p> <p>ELPBCs were modified to include a low-affinity GRGDS or GNGRG ligand and a unique conjugation site for hydrophobic compounds. This addition did not disrupt micelle self-assembly and facilitated thermally-controlled multivalency. The ability of ligand-ELPBC to specifically interact with isolated AvB3 or CD13 was tested using an in vitro binding assay incorporating an engineered cell line. RGD-ELPBC promoted specific receptor binding in response to multivalent presentation but NGR-ELPBC did not. Enhanced binding with multivalent presentation was also observed only with constructs exhibiting CMT < body temperature. This study establishes proof-of-principle of DAM, but ELPBC requires thermal optimization for use with applied hyperthermia. Static affinity targeting of fluorescent ligand-ELPBC was then analyzed in vivo using intravital microscopy (IM), immunohistochemistry (IHC), and custom image processing algorithms. IM showed increased accumulation of NGR-ELPBC in tumor tissue relative to normal tissue while RGD-ELPBC and non-ligand ELPBC did not, and IHC verified these observations. This study shows (1) multivalent NGR presentation is suitable for static multivalent targeting of tumors and tumor vasculature, (2) multivalent RGD presentation may be suitable for DAM with thermal optimization, and (3) ELPBC micelles may selectively target proteins at the tumor margin.</p> / Dissertation

The objective of this research is to investigate three classes of block copolymers, the vesicle structures they form, their response to stimuli in solution and their capabilities for use in biomimicry. The self-assembled structures of all classes of polymers will be used as a basis for templating hydrogel materials, in the interior of the vesicles, and the resulting particles will be designed to show the structural and mechanical properties similar to living cells. The synthetic block copolymers are a poly(ethylene glycol) and poly(butadiene) (PEO-b-PBd) copolymer, a poly(ethylene glycol) and a poly(dimethyl siloxane) (PEO-b-PDMS) copolymer and the polypeptide block copolymer is a lysine and glycine (K-b-G) copolymer. Investigation using the synthetic block copolymers will focus on whether the polymer can form vesicles, size limitations of vesicle structures, and the formation of internal polymer networks. Subsequent investigations will look at the needed steps for biomimicry. The PDMS copolymer is a novel entrant into amphiphilic block copolymers. Although characterization of the copolymer solution behavior is known, the mechanical properties of the polymer are not known. PDMS was investigated along with the PBd polymer due to the similar chemical structure and nature. The lysine-glycine copolymers are a new system of materials that form fluid vesicle structures. Therefore, characterization of how K-b-G assembly behavior and investigations of how K-b-G responds to solution conditions are needed before incorporating this copolymer into a cellular mimic. The size and mechanical behavior of the lysine-glycine vesicles are measured to compare and contrast to the synthetic systems. The goals in creating a biomimic are a hollow sphere structure with a fluid bilayer, a vesicle that has controllable mechanical properties, and with a controllable surface chemistry and density. Overall, these experiments were successful; the various properties are easily controllable: the size of vesicles created, the material properties of the vesicle interior and shell, as well as the surface chemistry of the vesicles. Investigations into the novel block copolymers were conducted, and the polypeptide block copolymer showed the ability to create vesicles that are responsive to changing salt and pH concentrations. The PDMS block copolymer system offers a new material system that will perform as well as the PBd system, but without some of the inherent drawbacks.

Nanostructures and properties of blends of homopolymer and elastomeric block copolymer nanoparticles were studied focusing on the effect of morphology and the viscoelastic properties on blends. The cylindrical and lamellar morphology of PS-b-PI copolymer was employed to generate the morphology of elastomeric nanoparticles such as nanofiber and nanosheet. The particles were synthesized using cold vulcanization process. The vulcanization process using sulfur monochloride (S2Cl2) was used to preserve the morphologies. The crosslinking density of block copolymer was controlled by exposure time of crosslinking agent in the chamber. The blend samples for DMA and rheometer were prepared using solvent casting process. The diameter and thickness of nanofiber and nanosheet obtained by the process were ~40 nm and ~70 nm, respectively. The rheological and dynamic mechanical properties of the blends of polystyrene (PS) and elastomeric nanoparticles were studied in terms of morphology and crosslinking density. The effect of core PI size also investigated and discussed. Based on these viscoelastic results, the theoretical percolation threshold was calculated and compared with experimental results. It is demonstrated that block copolymer is a facile method to generate elastomeric nanoparticles using cold vulcanization and viscoelastic properties can be tuned with addition of nanoparticles.

Self-organization of block copolymers becomes attractive for several branches of the current science and technology, which requires a cheap way of fabrication of well-ordered arrays of various nanoobjects. High ratio between the surface (or the interface) and the volume of the nanoobjects enables development of very efficient devices. The work within this thesis profits from the chemical dissimilarity between blocks of polystyrene-block-poly(4‑vinylpyridine) copolymers, where polystyrene forms “a body” of nanostructures and poly(4‑vinylpyridine) is “a link” for assemblies with low-molar-mass additives. Procedures and phenomena are demonstrated (observed) on few sorts of PS‑b‑P4VP copolymers with respect to their molecular weight and ratio of blocks. Although there are many kinds of nanostructures based on block copolymers, only nanotemplates are involved in the study. Their properties, like an influence of substrate roughness on microphase separation, stability of porous nanotemplates in ionized solutions, or a role of additives in their supramolecular assembly, respectively, are investigated. All of them appears to be important in development of various devices based on the nanotemplates. With respect to optoelectronic applications, electrical current transport and fluorescence are two basic phenomena studied on functionalized nanotemplates, developed in the thesis. DC transport is studied on nanostructures developed via sputtering of chromium into porous nanotemplates. Sputtering process is optimized in dependence of chromium deposition rate, composition and pressure of ambient gas. It is shown that a reactive nature of PS-b-P4VP nanotemplates enables development of resistant organometallic nanotemplates. On the other hand, suppression of the polymer reactivity is achieved by oxidation of a metal during sputtering in a reactive gas, which enables e. g. development of highly ordered TiO2 nanodots. Current-voltage characteristics are measured on “sandwich” devices (like LEDs) with various electrodes and composition. Several recent theoretical models fitting the characteristics are applied together with structural characterization techniques (like AFM or x-ray reflectivity) in order to elucidate relations among surface roughness, distribution of sputtered clusters, and carrier injection and transport. Fluorescence is studied on nanotemplates with organic low-molar-mass dyes, developed either via direct blending with the copolymer or via soaking of porous nanotemplates in dye solutions. Several relations between structure and fluorescence are observed. For instance, excimer emission in pyrene assemblies is supressed after ordering of the nanotemplate. Solvent induced orientation of fluorescein molecules in the nanotemplate results in fluorescence enhancement. Dimerization of Rhodamine 6G is dependent on the way of its impregnation in the nanotemplates (solvent, concentration, speed).

Block copolymers demonstrate potential in next-generation lithography as a solution for overcoming the limitations of conventional lithographic techniques. Ideal block copolymer materials for this application can be synthesized on a commercial scale, have high [chi]-parameters promoting self-assembly into sub-20 nm pitch domains, have controllable alignment and orientation, and have high etch contrast between the domains for facilitating pattern transfer into the underlying substrate. Block copolymers that contain silicon in one domain are attractive for nanopatterning since they often fulfill at least three of these requirements. However, silicon-containing materials are notoriously difficult to orient in thin films due to the low surface energy of the silicon-containing block, which typically wets the free surface interface. In this work, the methodology behind material choice and the synthesis of new silicon-containing block copolymers by a variety of polymerization techniques will be described. Thin film self-assembly of the block copolymers with domains oriented perpendicular to the plane of the substrate is achieved using different solvent annealing and neutral surface treatments with thermal annealing conditions. Block copolymer patterns are transferred to the underlying substrate by reactive ion etching and directed self-assembly of the polymers is demonstrated using chemical contrast patterns. Interesting thermodynamics governing the self-assembly of block copolymers with solvent annealing will also be discussed. Finally, new amphiphilic block copolymers will be described that were created with lithographic applications in mind but that are most useful for biological applications in drug delivery. / text

Στην παρούσα εργασία παρουσιάζεται η σύνθεση και η μελέτη υβριδικών υλικών, τα οποία αποτελούνται από νανοσωματίδια εγκλωβισμένα σε οργανικές και ανόργανες μήτρες. Τα υλικά που συντέθηκαν μπορούν να χωριστούν σε δύο κατηγορίες. Η πρώτη περιλαμβάνει μεταλλικά νανοσωματίδια Au και Ag εγκλωβισμένα σε πολυμερικές μήτρες, ενώ η δεύτερη κατηγορία περιλαμβάνει νανοσωματίδια Au, Ag και NiCl2 σε ανόργανες μήτρες. Η εργασία επικεντρώθηκε στην σύνθεση και την φασματοσκοπική μελέτη των υλικών χρησιμοποιώντας όλες τις διαθέσιμες τεχνικές δομικού χαρακτηρισμού των υλικών. Παράλληλα, πραγματοποιήθηκε μελέτη των οπτικών ιδιοτήτων και της χημειο-οπτικής ενεργότητας των υλικών. Επίσης, μελετήθηκε η βιοσυμβατότητα των υλικών στις περιπτώσεις που αυτό ήταν δυνατό. Αναλυτικότερα, στο μεγαλύτερο κομμάτι της εργασίας αυτής περιγράφεται η in situ σύνθεση μεταλλικών νανοσωματιδίων Au και Ag στον πυρήνα και στην κορώνα δισυσταδικών συμπολυμερών καθώς και τυχαίων συμπολυμερών. Το πρωτόκολλο που ακολουθήθηκε περιλαμβάνει τα παρακάτω βήματα: αρχικά για την διαλυτοποίηση του αμφίφιλου συμπολυμερούς επιλέγεται εκλεκτικός διαλύτης ως προς την μία συστάδα του, ώστε να σχηματιστούν μικκήλια αποτελούμενα από ένα συμπαγή πυρήνα και μια διαλυτή κορώνα. Στην συνέχεια, προστίθεται το άλας του μετάλλου στο διάλυμα του συμπολυμερούς με αποτέλεσμα είτε την εισροή του στον πυρήνα, είτε την συναρμογή του μεταλλικού ιόντος με την κορώνα ανάλογα με την χημική συνάφεια που φέρει η κάθε συστάδα ως προς το μέταλλο. Τέλος, ακολουθεί η αναγωγή του μεταλλικών ιόντων σε μεταλλικά νανοσωματίδια είτε προσθέτοντας κάποιο αναγωγικό μέσο, είτε από το ίδιο το συμπολυμερές που περιβάλλει τα μεταλλικά ιόντα. Η δεύτερη κατηγορία υλικών αφορά στην σύνθεση νανοσωματιδίων Au, Ag και NiCl2 σε ανόργανες μήτρες. Σε αυτή την περίπτωση επιλέχθηκαν πρόδρομες ενώσεις SiO2 και TiO2, οι οποίες αναμίχθηκαν με το άλας των μετάλλων ακολουθώντας την μέθοδο sol-gel ώστε να σχηματιστούν νανοσωματίδια. Μελετήθηκε η επίδραση των πειραματικών παραμέτρων, όπως η θέρμανση και η γήρανση, στο μέγεθος και τον βαθμό συσσωμάτωσης των μεταλλικών νανοσωματιδίων καθώς επίσης και στο πορώδες του τελικού υλικού. Από τα διαλύματα που προέκυψαν, σχηματίστηκαν λεπτά υμένια με την μέθοδο του spin-coating, τα οποία στην συνέχεια θερμάνθηκαν σε υψηλές θερμοκρασίες ώστε να απομακρυνθούν οι οργανικές ομάδες και να σταθεροποιηθεί το τελικό υλικό. Μέρος των υβριδικών υλικών που συντέθηκαν μελετήθηκαν ως προς την μη-γραμμική τους απόκριση χρησιμοποιώντας τις τεχνικές OKE και Z-scan. Όπως προέκυψε από τις μετρήσεις τα υλικά αυτά παρουσιάζουν μη-γραμμικότητα, η οποία εξαρτάται άμεσα τόσο από την αναλογία μετάλλου ως προς το συμπολυμερές αλλά και από την σύσταση του ίδιου του συμπολυμερούς. Τα νανοσύνθετα υλικά που συντέθηκαν αξιολογήθηκαν επίσης ως ενεργά υλικά σε πιθανούς φωτονικούς αισθητήρες. Παρατηρήθηκε ότι παρουσία ατμών μεθανόλης και αμμωνίας, συνέβαιναν μορφολογικές αλλαγές στην επιφάνεια των υλικών. Οι αλλαγές αυτές, ο οποίες καταγράφονται ως μεταβολές της διαδιδόμενης δέσμης σε σχέση με την δέσμη αναφοράς, είναι αντιστρεπτές. Τέλος, στις περιπτώσεις που τα υβριδικά υλικά που συντέθηκαν παρουσίαζαν βιοσυμβατότητα, ελέγχθηκε η ικανότητα συναρμογή τους με μόρια πρωτεϊνών και DNA και διερευνήθηκε η πιθανή εφαρμογή τους σε συστήματα βιολογικών παραγόντων. / In the present study the synthesis of hybrid materials consisting of metal nanoparticles incorporated into organic and inorganic matrices is presented. The synthesized materials can be divided into two categories; the first one consists of Au and Ag nanoparticles incorporated into polymeric matrices, while the second one consists of Au, Ag and NiCl2 nanoparticles incorporated into inorganic matrices. The thesis was focused on the synthesis and the spectroscopic study of these materials. Meanwhile, the optical and photonic properties of these materials were exploited. Moreover, the biological applications of the synthesized hybrid materials were investigated. In more detail, the larger part of this work focuses on the in situ synthesis of Au and Ag nanoparticles either inside the core or on the corona of di- and triblock copolymers and random copolymers. More specifically, the synthesis protocol requires three steps. First, the proper solvent must be chosen, which should be selective for one of the blocks of the amphiphilic copolymer, in order for micelles to be formed, consisting of a dense core and a solubilized corona. Then the metal precursor is added, which is preferentially dissolved into the core or is coordinated on the periphery of the corona block, depending on the chemical affinity that each block displays toward the metal compound. Finally, the metal ions are reduced in metal nanoparticles either by the addition of a reducing agent or by the coordinating block of the copolymer. The second category of the materials involves the synthesis of Au, Ag and NiCl2 nanoparticles inside inorganic matrices such as SiO2 and TiO2. Solutions containing SiO2 and TiO2 precursors were mixed with metal salts and the standard sol-gel methods were followed for the in situ synthesis of the hybrid materials. Thermal treatment and ageing were the two main parameters that influenced the size and the degree of aggregation of the metal nanoparticles, as well as the porosity of the final material. The non-linear optical properties of the synthesized hybrid materials were studied using the OKE and Z-scan techniques. All the materials studied displayed nonlinear refraction which was proportional to the ratio between the metal nanoparticles and the polymer. The composition of the block copolymer itself played also an important role. The hybrid nano materials were also evaluated as active components in potential photonic sensors. In the presence of methanol and ammonia, morphological changes on the surface of the materials were noticed. These changes were recorded as a signal modulation in respect to the reference signal. Finally, some of the synthesized hybrid materials displayed biocompatibility and their ability to coordinate with proteins and DNA molecules was examined, toward their utilization in bioanalytical devices.

This dissertation presents solid-state NMR studies that probe the dynamic and conformational properties of polymers adsorbed on solid surfaces in the dry state. The systems studied include a series of ethylene based random copolymers where the binding group is modified, and two diblock copolymer systems where the blocks have different intrinsic mobilities and surface interactions. The thesis begins by looking at the structures formed by the adsorption of poly (ethylene-co-acrylic acid) (PEA), poly (ethylene- co-vinyl alcohol) (EVOH), poly (ethylene-co-vinyl acetate) (EVA), and polyethylene (PE) on metal oxide powders (zirconia and alumina). NMR spectroscopy, FTIR-PAS, and TGA were used to characterize the surface behaviour of the systems with comparisons made between the bulk and adsorbed copolymers. 13C CPMAS, 1H and T 1 relaxation measurements were all recorded with the aim of correlating the microscopic structure of the surface with changes in NMR data. The chain conformation of adsorbed ethylene copolymers was found to strongly depend on the binding strength of the polar sticker groups with the substrates. / The chain dynamics of adsorbed diblock copolymers in the dry state are reported for the first time. Poly (styrene)-b-poly ( t-butyl acrylate) (PS-PtButA) and poly (styrene)-b-poly (acrylic acid) (PS-PAA) were selected to vary both the block size and the binding strength. Once again the primary surface characterization methods are NMR spectroscopy, FTIR-PAS, and TGA. 13C CPMAS, 1H, T1, and T1rho relaxation measurements were all recorded with the aim of correlating the surface structures with changes in NMR data. For the most part, the observed trends in the chain mobilities of the anchor (PAA) and buoy (PS) blocks with block size can be correlated with the predicted mushroom, intermediate and extended brush structures which collapse upon removal of the solvent. However, the chain mobility of the PS buoys decreases with increasing anchor block size. Although the chain mobility of the PS buoys are moderately enhanced relative to the bulk state, the mobility is sufficiently restricted to comfirm the picture of a thin glassy layer with adhesive properties similar to the surface of bulk polystyrene. / The diblock copolymers poly (2-vinylpyridine), poly (isoprene)- b-poly (2--vinylpyridine), (PI-P2VP) and poly (isoprene)- b-poly (4-vinylpyridine) (PI-P4VP) were selected to complement the PS-PAA system as both systems have been studied by surface force microscopy. The large contrast in chain mobilities of the PI and PVP blocks allowed spectral editing through variation of the 13C cross polarization parameters. The trends in mobility with block size differ from that of PS-PAA in that the segmental mobility of the buoys increases with anchor block size as expected. The chain mobility of the collapsed PI brushes is significantly enhanced as compared to the bulk state, again supporting the interpretation of surface microscopy studies which require an entropically unfavorable flattened, yet rubbery, surface structure.

This Ph.D. thesis reports the discovery and study of several morphologies of ABC triblock copolymer assemblies in block selective solvents. One block copolymer self-assembled into helices (mostly double and some triple helices), and the other block copolymer formed a mixture of structures resembling hamburgers and striped cylinders. The helices, biomimmetic structures which are unusual from block copolymer self assembly, were prepared from the triblock copolymer poly(n-butyl methacrylate)-block-poly(2-cinnamoyloxyethyl methacrylate)-block-poly(tert-butyl acrylate) (PBMA-b-PCEMA-b-PtBA). They were formed spontaneously in several binary solvent mixtures including dichloromethane/methanol, tetrahydrofuran (THF)/methanol, and chloroform/methanol. They were formed in the composition ranges where the mixtures were good for the PtBA block, poor for the PCEMA block, and marginal for the PBMA block. The structure was studied and established by TEM, AFM, DLS and 1H NMR and by TEM tomography. The mechanism and kinetics of helix formation was examined. The Hamburger and striped cylinder structures were produced from poly(tert-butyl acrylate)-block-poly(2-cinnamoyloxyethyl methacrylate)-block-poly(succinated glyceryl monomethacrylate) or (PtBA-b-PCEMA-b-PSGMA) in mixtures of THF, (-)-sparteine and 1- or 2-propanol. Here THF solubilized all the blocks of the copolymer, while propanol was a precipitant for the middle block (PCEMA), and the chiral amine, (-)-sparteine, complexed with PSGMA and made it insoluble. Within the Hamburger-like structure, the “filling” was made of the complexed PSGMA chains and the "buns" were made of PCEMA. The striped cylinders were made of stacking alternating PCEMA and PtBA stubs. The PtBA chains were located on the outer surfaces of both of these structures. With the hamburger structures, after PCEMA crosslinking, we were able to remove the chiral amine by dialysis and make the PSGMA chains soluble again in solvents such as N, N dimethylformamide. The hamburgers were thus separated into two halves, with each half existing as a Janus particle, which had PtBA chains on one side and PSGMA chains on the other side. The Janus particles might have interesting applications, such as in Pickering emulsion stabilization. / Thesis (Ph.D, Chemistry) -- Queen's University, 2010-04-30 18:01:06.281

This thesis describes the examination of novel block copolymers that contain Ru(bpy)32+ complexes incorporated into one block of diblock copolymers made by ROMP. With the intent of exploring the potential usefulness of these interesting materials in applications such as light-harvesting and sensing, a systematic study of the solution self-assembly, luminescence properties, and the ability of the metal complex to engage in electron and energy transfer reactions has been conducted. / The solution self-assembly of block copolymers that contain Ru(bpy) 32+ complexes was examined first. Using a series of these block copolymers, a detailed study of the effects of block length, block ratio, polymer concentration and solution conditions on the copolymer self-assembly is presented. Using TEM, a number of morphologies were reproducibly observed including star micelles, large compound micelles, tubules, and interestingly, vesicles. These structures all contain the metal complex Ru(bpy)3 2+ within their core domains. / The luminescence properties of two block copolymers containing Ru(bpy) 32+ were examined: one polymer self-assembled into star micelles, the other into vesicles. Comparison of the unassembled polymer chains and the self-assembled polymers indicated that self-assembly, and confinement of the Ru(bpy)32+ complexes into the core domains of the aggregates, did not seriously adversely affect the luminescence properties of the metal complex. Measurement of the luminescence lifetime decay of the polymers suggested that energy migration occurred among the metal complexes along the polymer chain. The ability of the metal complexes within self-assembled structures to participate in electron transfer reactions with small molecules was also explored. It was found that from within the core domains of self-assembled structures, the Ru(bpy)32+ complexes could still engage in electron transfer reactions with molecules on the outsides or the insides of the aggregates, likely a result of energy migration. / The ability of Ru(bpy)32+ complexes within the cores of micelles to participate in energy transfer was explored. Micelles were formed in aqueous solutions using polymers that possessed both the metal complex and a water-soluble block. Several methods were attempted to encapsulate two molecules, a derivative of coumarin 2 and an Os(bpy)3 2+-based molecule, inside these micelles. It was observed that Ru(bpy) 32+ could act as an energy acceptor from the coumarin derivative, and could act as an energy donor to the osmium-based complex. Encapsulation of the small molecules greatly enhanced the efficiency of energy transfer, by non-covalently bringing the small molecules in close proximity to the Ru(bpy)32+ complexes. / Polymers were synthesized that contained a Ru(bpy)3 2+-based block and were terminated with the molecular recognition unit biotin. These polymers, upon self-assembly, formed micelles with biotin groups on their periphery. The addition of the protein streptavidin, which has a strong binding affinity for biotin, resulted in the aggregation of the self-assembled structures. This established the potential for self-assembled metal-containing aggregates to form higher-order structures. / Early work is presented in Appendix A involving block copolymers that contain hydrogen-bonding groups. Several methods were attempted to elucidate the solution morphologies of these polymers, namely IR, 1H NMR, DLS, and pyrene fluorescence. The transition of this initial work to polymers that contain the Ru(bpy)32+ complex is also described.