Browsing by Subject "Block copolymer"

Now showing 1 - 11 of 11
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    Block copolymer Ion gels for CO2 Separations
    (2013-08) Gu, Yuanyan
    Block copolymer ion gel is composed of a polymer network formed by self-assembly of triblock copolymers, and an ionic liquidIn this thesis project, the target is to study the gas separation performance of ion gels for CO2 separation, and seek ways to optimize their properties in terms of the gas separation performance and mechanical strength. Ionic liquids have shown great promise as novel CO2-separation media, largely due to their highly selective gas solubility and non-volatility. It is discovered that the polymer networks not only provides the mechanical support to the ionic liquid, but help improve the gas separation performance as well.To study the CO2 separation performance of block copolymer ion gels, model ion gel systems that comprise 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMI][TFSA]), and a triblock copolymer with a polymerized ionic liquid mid-block was prepared.. The gas separation performance was measured on a supported ion gel membrane. It was discovered that the polymerized ionic liquid gels exhibit high gas permeability due to the high liquid fraction. Moreover, the permeation selectivity is significantly increased from that of the neat ionic liquid. Comparisons with Robeson plots also indicate very promising separation performance for ion gels. Two other ion gels formed by self-assembly of poly(styrene-b-ethylene oxide-b-styrene) (SOS) and poly(styrene-b-methyl methacrylate-b-styrene) (SMS) in [EMI][TFSA] were also examined. The separation performance of ion gels was found to be strongly dependent on the polymer mid-block. It is also desirable to enhance the mechanical properties of ion gels. A novel ion gel based on poly[(styrene-r-vinylbenzyl azide)-b-ethylene oxide-b-(styrene-r-vinylbenzylazide)] (SOS-N3) was synthesized. Such a triblock copolymer ion gel can be chemically cross-linked by high temperature annealing and UV-irradiation. After cross-linking, the mechanical strength of the gel showed significant improvement, with 400% increase in the tensile strength and almost one order of magnitude increase in toughness. The mechanical stability of the supported ion gel membranes was also enhanced. More importantly, the mass transport properties are retained after the cross-linking. Overall, block copolymer ion gels represent a promising class of materials for CO2 separation applications. Through rational choice of ionic liquid and block copolymers, the properties of ion gels can be further optimized.
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    Block copolymer self-assembly in solution: structure and dynamics.
    (2010-08) Choi, Soo-Hyung
    Block copolymers can self-assemble into micelles or vesicles when dispersed in a selective solvent. In this study, spherical micelles were formed by poly(styrene-bethylene- alt-propylene) (PS-PEP) in squalane, highly selective to PEP blocks, leading to PS cores and swollen PEP coronas. The micelle structure was characterized by dynamic light scattering (DLS) and small-angle x-ray scattering (SAXS). The experimental results provide a detailed picture of micelle structure and intermicelle interaction as a function of block copolymer molecular weight and composition, concentration, and temperature. Based on this structural information, the single molecular exchange kinetics between the spherical micelles in dilute solution was examined by time-resolved small-angle neutron scattering (TR-SANS). Two pairs of structurally matched partially protonated and deuterated micelles were prepared and each pair was blended to provide an initially isotopically segregated state in solution. The SANS intensity is directly related to the concentration of protonated chains in the micelle cores. Therefore, a reduction in the measured scattering intensity can be quantitatively correlated with the exchange of chains. This measurement was aimed at probing the dependence of molecular exchange kinetics on temperature, molecular weight, and concentration. The temperature dependence of the chain exchange rate R(t) can be explained based on the core block dynamics, while the documented quasi-logarithmic decay of R(t) is shown to be consistent with single chain exchange that is hypersensitive to the core degree of polymerization and therefore polydispersity. Complementary measurements were also conducted with concentrated solutions where the micelles pack onto a body-centered cubic lattice. Based on a first-principles model, the exchange kinetics are expected to be independent of micelle concentration. However, slower dynamics in ordered micelles were observed. These results suggest that contributions from factors other than core block dynamics can come into play in the exchange kinetics for ordered micelles.
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    Data for Thermodynamics and morphology of linear multiblock copolymers at homopolymer interfaces
    (2023-11-09) Collanton, Ryan P; Ellison, Christopher J; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D
    Block copolymers at homopolymer interfaces are poised to play a critical role in the compatibilization of mixed plastic waste, an area of growing importance as the rate of plastic accumulation rapidly increases. Using molecular dynamics simulations of Kremer–Grest polymer chains, we have investigated how the number of blocks and block degree of polymerization in a linear multiblock copolymer impacts the interface thermodynamics of strongly segregated homopolymer blends, which is key to effective compatibilization. The second virial coefficient reveals that interface thermodynamics are more sensitive to block degree of polymerization than to the number of blocks. Moreover, we identify a strong correlation between surface pressure (reduction of interfacial tension) and the spatial uniformity of block junctions on the interface, yielding a morphological framework for interpreting the role of compatibilizer architecture (number of blocks) and block degree of polymerization. These results imply that, especially at high interfacial loading, the choice of architecture of a linear multiblock copolymer compatibilizing surfactant does not greatly affect the modification of interfacial tension.
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    Diblock copolymer stabilized nanoparticles for drug delivery via flash nanoprecipitation
    (2014-10) Han, Jing
    Cancer is one of the most challenge diseases to treat around the world. Drug delivery system, as one of the chemotherapeutic treatments has received enorrmous attention from researchers. This thesis is to develop amphiphilic diblock copolymer protected nanoparticles loaded with anti-cancer drug, with small size and high drug loading, to achieve selective drug delivery using EPR effect. Chapter 1 briefly describes the motivation and novelties of this research pursuit. Chapter 2 introduces a modified confined impingement jets mixer with dilution (CIJ-D mixer), using flash nanoprecipitation to produce nanoparticles made of hydrophobic drugs. The CIJ-D mixer was evaluated by the sizes of β-carotene nanoparticles at varied flow conditions compared to these made by multi-inlet vortex mixer. The CIJ-D mixer provides higher efficiency and easiness of handling for nanoparticle preparation. That is why CIJ-D mixer was used for all the work presented in the following chapters. In Chapter 3, we made the first attempt to produce PEG-b-PLGA protected paclitaxel loaded nanoparticles but failed, because paclitaxel is too hydrophilic to be captured in particles. Thus, a series of silicate ester derivatized paclitaxel were synthesized by Hoye research group and successfully encapsulated into nanoparticles. Several nanoparticle post-treatments, such as filtration, hollow fiber diafiltration, and ultracentrifugation were used and assessed, in order to purify nanoparticles. Lyophilization was found to induce nanoparticle aggregation due to the freezing process. The addition of sucrose as cryoprotectant was studied to prevent aggregation and recover nanoparticle. Chapter 4 focuses on developing in vitro drug release protocols, for more accurate quantification of highly hydrophobic paclitaxel prodrugs. Different dialysis devices were used such as dialysis tubes, dialysis cassettes, and dialysis mini capsules. Infinite sink and limited sink conditions were compared as well to provide sufficient concentration gradient across dialysis semi-permeable membrane. At last, a reverse drug release experimental protocol was customized to determine the remaining drug left in dialysis mini capsules while the sink condition was maintained by frequently refreshing buffer solution during in vitro drug release study. Chapter 5 mainly presents the pharmacokinetics of paclitaxel prodrug nanoparticles loaded with different silicate ester derivatives, at different pH, both inside nanoparticles and in buffer solution. Chapter 6 includes a series of Cryo-TEM images of nanoparticles collected at different time, such as fresh nanoparticles immediately after being prepared by CIJ-D mixer, nanoparticles after ultracentrifugation, after lyophilization, 0hr, and 24 hr during drug release study. These images not only showed a reverse liner relation of average particle size and hydrophobicity of the loaded drug, but also displayed a core-shell internal structure of nanoparticles prepared via flash nanoprecipitation and potential particle disassembly after 24hr drug release. Finally, Chapter 7 summarizes the key results and conclusions obtained from previous chapters, lessons learned from mistakes and failures, and future directions for this project, in order to prepare nanoparticles with better controlled size and drug release kinetics and to understand deeply on nanoparticle formation and release mechanisms.
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    Phase behaviors of ABAC tetrablock terpolymers
    (2012-11) Zhang, Jingwen
    The thesis focuses on the composition and the asymmetric effect on the phase behaviour of the tetrablock terpolymers using poly(styrene-b-isoprene-b-styrene-bethylene oxide) (SISO) as the model system, synthesized via a living anionic polymerization method and characterized with NMR, GPC, TEM, SAXS, DSC and DMS. In the compositional study, two series of the isoprene-rich and the styrene-rich symmetric SISO samples (the S blocks are divided equally) are studied in addition to the series with equal volume fractions of the S and I blocks. In the isoprene-rich series, the hexagonally ordered core-shell spherical and cylindrical morphologies (P6/mmm and P6/mm space group symmetries) have been identified with increasing O contents. The temperature dependence is examined using one specimen in the isoprene-rich series near the order-disorder boundary. A dodecagonal quasicrystalline (QC) phase has been identified to occur as an intermediate state between the simple hexagonal order (P6/mmm) and the Frank-Kasper σ-phase ( P /mnm 42 ) before the sample disorders, with THEX < TQC < Tσ < TODT. The TEM results reveal a QC morphology with a 12-fold rotational symmetry and the existence of the local dodecagonal quasicrystalline approximants that lack of any long-range translational order. The sequence of phases in the styrene-rich SISO series is the disordered state, spheres with a BCC lattice, liquid-like packed (LLP) spheres and the hexagonally (HEX) ordered cylinders. For SISO with fO = 11%, LLP, 12-fold QC after shorter annealing time of 30 minutes and Pm3n phase after longer annealing time of one day, σ-phase and the disordered states are formed with increasing temperatures; and for another SISO with fO v = 15%, the LLP spheres and HEX cylinders are formed. Changing the molecular architecture from the ISO triblocks to the SISO tetrablocks drives the preference from the hyperbolic interfaces inherent in the network morphologies to the higher, and zero Gauss, curvature surfaces present in the core-shell spheres and cylinders. In the asymmetric study, the asymmetric parameter τ = NS/(NS+NS’) = 0.21 – 0.70 is the only variable. The core-shell spheres on a hexagonal lattice and LLP have been observed at lower temperatures; the 12-fold QC phase with shorter annealing time of 30 minutes and the Pm3n phase after longer annealing time of one day have been observed at intermediate temperatures before the Frank-Kasper σ-phase is formed at the higher temperatures before the samples disorder. The phase behaviors of the symmetric SISO and the asymmetric SIS’O tetrablock terpolymers are nearly identical. Overall, six, and possibly more, sphere-forming phases have been identified in the SISO tetrablock terpolymers: BCC ( Im3m ), LLP, P6/mmm, QC, Pm3n and P /mnm 42 (σ-phase). These phases indicate the great design flexibility and opportunities for the novel phase formation with the ABA’C tetrablock molecular architecture at various molecular weights and compositions
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    Realizing Enhanced Toughness in Block Copolymer Modified Brittle Plastics
    (2016-08) Li, Tuoqi
    The great commercial importance of several brittle plastics continuously drives research efforts to be devoted to fabricating well defined structures in these materials for effectively toughening them. Amphiphilic block copolymers can be appropriately designed to generate nanometer scaled structures in a brittle plastic matrix at relatively low loadings (< 5% by weight). The resultant nanostructured plastics exhibit significant toughness enhancement without sacrificing other desirable properties such as transparency, stiffness and use temperature. The goal of this dissertation is to understand the nanostructure formation of block copolymers and the consequent toughening effect under various conditions. In this work we designed different types of block copolymer modifiers in concert with several commercially important brittle plastics, including epoxy thermosets and poly(lactide) (PLA) thermoplastics. The block copolymer toughening strategy was first established in bulk epoxies as well as in epoxy coatings through a model system study with the Jeffamine resin. Two distinct types of diblock copolymers formed spherical micelles in cured bulk epoxies and 15 micrometer thick coatings, but the process of solvent-casting affected the micelle size and distribution in the coating. The toughness enhancement observed in bulk epoxies (up to 5-fold increase in the critical strain energy release rate GIc) successfully translated to coatings, as evidenced by the over 40% increase in the coating abrasive wear resistance with only 5 wt.% of modifiers. Transmission electron microscopy (TEM) revealed that similar toughening mechanisms as those in bulk epoxies (micelle cavitation and matrix shear yielding) still held in thin coatings. Moreover, the hardness, modulus, transparency and glass transition temperature (Tg) of modified coatings were not appreciably affected compared to unmodified ones. Based on this model system study, we proceeded to investigate the commercially viable Cardolite resin system that is more complex thermodynamically but industrially relevant. A series of poly(ethylene oxide)-b-poly(butylene oxide) (PEO-PBO) diblock copolymers were synthesized at fixed composition (31% PEO by volume) and varying molecular weight expanding on a commercial product under the tradename Fortegra™ 100. Direct application of this product resulted in little improvement of the poor fracture toughness of the cured material. Modification of the resin formulation and curing protocol led to the development of well-defined spherical and branched wormlike micelles in cured resins. Thermodynamic interactions and the curing reaction together controlled the micelle formation as evidenced by small angle x-ray scattering (SAXS) measurements. A 9-fold increase in GIc over the neat bulk epoxy, and an over 30% improvement in the coating abrasive wear resistance over the unmodified coating were achieved at 5 wt.% loading of wormlike micelles. We then took one step further to explore the toughening efficacy of block copolymer micelles in hybrid composite systems in the presence of a second type of modifier, rigid graphene fillers with amine-functionalization. Both types of modifiers were well dispersed in cured epoxies with no observable interactions under TEM. The crosslink density of the epoxy network strongly affected the toughening effect. In the matrix with the lowest crosslink density, the combination of micelles and graphene drastically enhanced the GIc value to 19 times that of the neat material with no reduction in the elastic modulus and Tg. Additionally, hybrid ternary composites exhibited a synergistic toughening effect, revealing some positive mutual interference to the toughening mechanisms noted for micelles and graphene particles. Lastly, we extended the block copolymer toughening strategy to the PLA thermoplastic matrix. A low molar mass PEO-PBO diblock copolymer was uniformly dispersed as short cylindrical micelles in a commercial high molecular weight glassy PLLA plastic. This structure formation resulted from the negative Flory-Huggins interaction parameter (X) between PEO and PLLA. Those micelles could effectively toughen the matrix through concurrent cavitation, crazing and shear yielding. At only 5 wt.% of loading, micelles led to a greater than 10-fold increase in the tensile toughness and notched Izod impact strength over the neat PLLA in the glassy state. This toughening effect was retained in plastic films prepared with modified blends via a film blowing process.
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    Self-assembly of block copolymers in thin films
    (2013-08) Kim, Sangwon
    The self-assembly of block copolymers in thin films has been a subject of recent studies from both academic and industrial perspectives. One of its potential applications is nanolithography; block copolymers can function as novel mask materials intended for fabrication of small features, not easily realizable by current optical lithography. This dissertation addresses several fundamental issues associated with thin-film block copolymers. The bulk and interfacial wetting properties of partially epoxidized poly(styrene-b-isoprene) diblock copolymers, denoted as PS-PEI, were studied while varying the degree of the chemical modification. The incorporation of the random copolymer architecture induced decoupling between the bulk and the thin-film thermodynamics. The tunable surface wetting, a consequence of the partial modification, permitted control over the orientation of the domains in thin films. The morphologies of thin-film block copolymers were investigated using two different boundary conditions that involve one neutral interface and one preferential interface. The neutralities at the free surface and the underlying substrate were attained independently by the partial epoxidation in PS-PEI and the composition adjustment of random copolymer mats, respectively. For both boundary conditions, thin-film block copolymers formed an island/hole motif, characterized by 0.5 L0 step heights (L0: bulk lamellar periodicity). The thin-film behavior of PS-PEI block copolymers with random copolymer architecture was examined as the segregation strength (χN) was adjusted systematically across the order-disorder transition. Unlike in the bulk, the random copolymer architecture did not generate abnormal behavior in thin-film thermodynamics compared to plain linear architecture. With decreasing segregation strength, the thin-film system exhibited fluctuation-pervaded morphologies prior to reaching a disordered state. An agreement was found between the order-disorder transition temperatures in three dimensions (bulk) and in two dimensions (thin film). Lastly, the bulk properties and the thin-film structures of lamellae-forming poly(styrene-b-isoprene-b-methyl methacrylate) (SIM) triblock copolymers were studied. The thin-film morphology exhibited the dependence on the size of the poly(isoprene) (PI) middle block. While perpendicular lamellae were observed for the thin-film SIM block copolymer with a small PI volume fraction, complex behavior was observed for the sample with a large PI volume fraction.
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    Structure and Chain Exchange Kinetics of Block Copolymer Micelles in Selective Solvents
    (2017-08) Ma, Yuanchi
    Block copolymers can self-assemble into various structures, such as micelles and vesicles. Previous studies have shown that single chain exchange is the main mechanism for block copolymer micelles to achieve equilibrium. In this study, a new lower critical micelle temperature (LCMT) system, poly(methyl methacrylate)-block-poly(n-butyl methacrylate) in two room temperature ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide was developed, and its chain exchange kinetics were investigated using time-resolved small-angle neutron scattering (TR-SANS). In order to probe the effect of the core block length, the corona block length and the solvent selectivity on the chain exchange rate, we synthesized two series of protonated and deuterated copolymers, one with identical core block length and one with identical corona block length, as well as systematically varied the Flory-Huggins interaction parameter χ by tuning the ratio of the two ionic liquids in the solvent. Notably, the results show that the solvent selectivity has a remarkable effect on the chain exchange rate, and therefore we proposed a more elaborate function of χ for the energy barrier of chain expulsion, which is rationalized by a calculation in the spirit of Flory−Huggins theory. Besides the kinetic study, complementary dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) experiments were also conducted to investigate the structure of micelles. Particular emphasis was placed on elucidating the scaling relationship between the micelle core radii and the degree of polymerization of the core block in the copolymers.
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    Structure and dynamics of block copolymer based soft materials
    (2011-02) Lee, Sangwoo
    Block copolymers are made by joining two or more polymer components into a single molecule. Due to the incompatibility between the interconnected chains, block copolymers form microphase separated domains of long range order at length scales of 5 - 100 nm. These materials have been the subject of intense study for the past four decades and the rich structural and dynamic behavior of block copolymers are still being explored. In this thesis, the structure, dynamics and mechanical properties of block copolymers and block copolymer blends were investigated using small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), dynamic mechanical spectroscopy (DMS), differential scanning calorimetry (DSC), and tensile testing. A new equilibrium block copolymer phase, the Frank-Kasper σ-phase was discovered in poly(1,4-isoprene-b-DL-lactide) (IL) diblock and poly(styrene-b-1,4- isoprene-b-styrene-b-ethylene oxide) (SISO) tetrablock copolymer melts. The σ-phase has tetragonal symmetry (P42/mnm) and possesses 30 spheres per unit cell. This gigantic crystal, a dodecagonal quasicrystal approximant, structure has been reported primarily in two heavy metals, numerous metal alloys, and dendrimers. Identification of the σ-phase in block copolymers provides new evidence regarding the complex nature of packing spheres on an ordered lattice. The dynamics ordered sphere-forming block copolymers was studied using SAXS and rheological techniques. The process of ordering into a body-centered cubic (BCC) morphology from the disordered state and the order-to-order transition (ODT) from the (metastable) BCC to σ-phase were found to follow nucleation and growth mechanisms. The IL diblock copolymer phase diagram was investigated as a function of composition and temperature. IL diblock copolymers are strongly segregated due to a relatively large Flory-Huggins interaction parameter χ between polyisoprene and poly(DL-lactide). Fluctuation effects strongly influence the ODT due to the low IL molecular weights and this was evidenced by thermal signatures in DSC thermograms. The structure and mechanical properties of poly(DL-lactide-b-1,4-isoprene-b-DLlactide) (LIL) triblock copolymer thermoplastic elastomer and low molecular weight IL diblock copolymers, and blends of these materials were studied. While the linear response is relatively invariant to the molecular architecture and molecular weight, the extensional properties were dramatically influenced by the triblock content. Finally, path dependency of microstructures of poly(1,2-butadiene-b-ethylene oxide) (PB-PEO) non-ionic block copolymer surfactants in oil and water was examined. Due to an extremely low critical micelle concentration due to the high molecular weight of the PB-PEO block copolymer surfactant, highly path dependent and long-lasting metastable microstructures were generated. This result offers new opportunities for the preparation of target block copolymer microstructures.
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    Structure and mechanical properties of multiblock copolymers: toward the development of enhanced mechanical response materials
    (2014-01) Lee, Intaek
    Block polymers have attracted scientific interest for decades, and most studies have focused on the simplest molecular architectures: linear AB diblock and ABA triblock copolymers. Multiblock copolymers containing a large number of blocks are expected to have distinct microstructures and a mechanical response which is different from that of conventional diblock and triblock copolymers. This research addresses synthesis and characterization of poly(cyclohexylethylene)-polyethylene (CECECECEC) nonablock copolymers, poly(styrene-b-butadiene) (PS-PB) multiblock copolymers, and poly(lactide-b-butadiene) (PLA-PB) multiblock copolymers. CECECECEC nonablock copolymers having a large center C block were synthesized using sequential anionic polymerization followed by catalytic hydrogenation. The CECECECEC samples exhibited different morphologies with varying size of PE blocks. As the PE block size increased, the microstructure was transformed with the sequence of disordered homogeneous phase - lamellae with mixed phase of outer CECE blocks - layer-in-layer microstructure. Moreover, the secondary phase segregation of outer CECE blocks allowed tough mechanical behavior. PS-PB multiblock copolymers with alternating and random block sequences were synthesized using a combination of living anionic polymerization and polycondensation. Molecular characterization revealed the successful synthesis of the desired multiblock products through the proposed procedure. Structural analysis demonstrated a random bicontinuous-like morphology over a wide range of compositions, 0.69 ≤ fPS ≤ 0.85. Tensile tests showed yielding followed by necking and an overall ductility that translates into much greater toughness than that typically found in glassy continuous SBS triblock copolymers. PLA-PB multiblock copolymers (0.5 ≤ fPLA ≤ 0.9) were synthesized in a two-step procedure: PLA-PB-PLA triblock copolymers were prepared using ring-opening polymerization, followed by chain extension with the condensation reaction. Multiblock copolymer and homologous triblock materials exhibited nearly identical and well-ordered morphologies, in sharp contrast with the findings of PS-PB multiblock polymers. These results indicate a transition from classically ordered morphologies to a state of bicontinuous disorder for multiblocks containing <n> ≥ 10, where <n> is the average total number of blocks. In tensile tests, most PLA-PB multiblock copolymers exhibited dramatically enhanced mechanical properties compared to the corresponding LBL triblock copolymers. These results suggest that a multiblock copolymer strategy offers new possibilities to obtain unique microstructures and physical properties from many other combinations of polymers.
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    Synthesis and characterization of silicate ester prodrugs and poly(ethylene glycol)-b-poly(lactic-co-glycolic acid) block copolymers for formulation into prodrug-loaded nanoparticles
    (2012-09) Wohl, Adam Richard
    Fine control of the physical and chemical properties of customized materials is a field that is rapidly advancing. This is especially critical in pursuits to develop and optimize novel nanoparticle drug delivery. Specifically, I aim to apply chemistry concepts to test the hypothesis "Silicate ester prodrugs of paclitaxel, customized to have the proper hydrophobicity and hydrolytic lability, can be formulated with well-defined, biocompatible, amphiphilic block copolymers into nanoparticles that are effective drugs." Chapter 1 briefly describes the context and motivation of the scientific pursuits described in this thesis. In Chapter 2, a family of model silicate esters is synthesized, the hydrolysis rate of each compound is benchmarked, and trends are established based upon the steric bulk and leaving group ability of the silicate substituents. These trends are then applied to the synthesis of labile silicate ester prodrugs in Chapter 3. The bulk of this chapter focuses on the synthesis, hydrolysis, and cytotoxicity of prodrugs based on paclitaxel, a widely used chemotherapeutic agent. In Chapter 4, a new methodology for the synthesis of narrowly dispersed, "random" poly(lactic-co-glycolic acid) polymers by a constant infusion of the glycolide monomer is detailed. Using poly(ethylene glycol) as a macroinitiator, amphiphilic block copolymers were synthesized. Co-formulating a paclitaxel silicate and an amphiphilic block copolymer via flash nanoprecipitation led to highly prodrug-loaded, kinetically trapped nanoparticles. Studies to determine the structure, morphology, behavior, and efficacy of these nanoparticles are described in Chapter 5. Efforts to develop a general strategy for the selective end-functionalization of the polyether block of these amphiphilic block copolymers are discussed in Chapter 6. Examples of this strategy include functionalization of the polyether with an azide or a maleimide. Finally, Chapter 7 provides an outlook for future development of the strategies described in this thesis and summarizes the results and conclusions of the experimental results that led to the development of the therapeutic, paclitaxel silicate-loaded, polymeric nanoparticles.