Synthesis, Characterization and Amphiphilic Self-assembly of Inorganic Nanoparticles Functionalized with Polymer Brushes of Variable Composition and Chain Length PDF Download
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Author: Brian Coleman Publisher: ISBN: Category : Languages : en Pages :
Book Description
The synthesis, characterization and amphiphilic self-assembly of polymer brush functionalized nanoparticles (PBNPs) using a block copolymer template is described herein. To study the effect of polymer brush composition on self-assembly, four samples were created using a mixture of PS-b-PAA (polystyrene-block-polyacrylic acid) and PMMA-b-PAA (poly(methyl methacrylate)-block-polyacrylic acid) diblock copolymers to create PBNPs with a CdS quantum dot (QD) core and different ratios of PS and PMMA in the coronal brush. Static light scattering showed that despite differences in brush composition, the PBNPs formed nanoparticles of similar aggregation number and chain density but showed evidence of asymmetric structure in a common solvent for both blocks at higher PS contents. After subsequent hydrolysis of the hydrophobic PMMA to hydrophilic poly(methacrylic acid) (PMAA), these amphiphilic particles were then self-assembled in THF/H2O solution in which it was determined that increasing the hydrophobic content of the brush composition, the initial nanoparticle concentration (c0) or the added salt content (RNaCl), would cause the assembly of low curvature assemblies. Compilation of this data allowed for the construction of phase diagrams for PBNP systems based on brush composition and c0 at different salt contents. Lastly, PS-b-PAA-b-PMMA triblock copolymers with variable PMMA chain length were assembled into PBNPs around a CdS QD core using a block copolymer template approach. Light scattering showed these particles also had similar aggregation number and chain density despite the difference in PMMA chain length. After hydrolysis of PMMA to PMAA these particles were then self-assembled in THF/H2O mixtures to determine the role of PMAA block length on the produced morphological structures. The resulting assemblies suggest that chain length played a minimal role in their self-assembly.
Author: Brian Coleman Publisher: ISBN: Category : Languages : en Pages :
Book Description
The synthesis, characterization and amphiphilic self-assembly of polymer brush functionalized nanoparticles (PBNPs) using a block copolymer template is described herein. To study the effect of polymer brush composition on self-assembly, four samples were created using a mixture of PS-b-PAA (polystyrene-block-polyacrylic acid) and PMMA-b-PAA (poly(methyl methacrylate)-block-polyacrylic acid) diblock copolymers to create PBNPs with a CdS quantum dot (QD) core and different ratios of PS and PMMA in the coronal brush. Static light scattering showed that despite differences in brush composition, the PBNPs formed nanoparticles of similar aggregation number and chain density but showed evidence of asymmetric structure in a common solvent for both blocks at higher PS contents. After subsequent hydrolysis of the hydrophobic PMMA to hydrophilic poly(methacrylic acid) (PMAA), these amphiphilic particles were then self-assembled in THF/H2O solution in which it was determined that increasing the hydrophobic content of the brush composition, the initial nanoparticle concentration (c0) or the added salt content (RNaCl), would cause the assembly of low curvature assemblies. Compilation of this data allowed for the construction of phase diagrams for PBNP systems based on brush composition and c0 at different salt contents. Lastly, PS-b-PAA-b-PMMA triblock copolymers with variable PMMA chain length were assembled into PBNPs around a CdS QD core using a block copolymer template approach. Light scattering showed these particles also had similar aggregation number and chain density despite the difference in PMMA chain length. After hydrolysis of PMMA to PMAA these particles were then self-assembled in THF/H2O mixtures to determine the role of PMAA block length on the produced morphological structures. The resulting assemblies suggest that chain length played a minimal role in their self-assembly.
Book Description
This first book on this important and emerging topic presents an overview of the very latest results obtained in single-chain polymer nanoparticles obtained by folding synthetic single polymer chains, painting a complete picture from synthesis via characterization to everyday applications. The initial chapters describe the synthetics methods as well as the molecular simulation of these nanoparticles, while subsequent chapters discuss the analytical techniques that are applied to characterize them, including size and structural characterization as well as scattering techniques. The final chapters are then devoted to the practical applications in nanomedicine, sensing, catalysis and several other uses, concluding with a look at the future for such nanoparticles. Essential reading for polymer and materials scientists, materials engineers, biochemists as well as environmental chemists.
Author: Litao Bai Publisher: ISBN: Category : Electronic dissertations Languages : en Pages : 193
Book Description
Functionalized nanoparticles and their assembly have been the subject of intense recent research activity. The stability and assembly of functionalized nanoparticles are still challenges for practical applications. Polymers are excellent stabilizing agents which can be used in nanoparticles synthesis. This dissertation describes polymer mediated nanoparticles which synthesized by both chemical and photo reduction techniques. The synthesis methods and assembly of polymer mediated nanoparticles were systematically studied. Two kinds of polymers were used in this research: PAMAM dendrimer and hyperbranched polyethylenimine. PAMAM dendrimer was used as the host for the synthesis of FePt nanoparticles with narrow size distribution by chemical reduction. Magnetic and structural properties of the as-made and annealed samples were studied. The as-made FePt nanoparticles have the chemically disordered fcc structure and can be transformed into the chemically ordered fct structure after annealing. But the annealing process caused both the size and size distribution to increase. To prevent size increase during annealing, dendrimer mediated alloys were encapsulated in silica microspheres. Their magnetic properties can be manipulated by synthesis conditions. Polyethylenimine is a kind of hyperbranched polymer, which was used to encapsulate nanoparticles. With polyethylenimine, Pt and Co3O4 nanoparticles were synthesized by photochemical processes. Their formation mechanisms were discussed. The chemical and electrochemical catalytic activity of polyethylenimine mediated Pt nanoparticles were studied. The results indicate that polyethylenimine is a good capping and reducing agent, and a carrier which improve samples stability and allows patterning. Ordered discrete magnetic nanoparticle arrays were also fabricated. Polyethylenimine was used as a stabilizer to synthesize magnetite nanoparticles. Polyethylenimine coating of magnetite nanoparticles can effectively prevent the aggregation of the nanoparticles. By combining the capillary filling technique with a magnetic field, polyethylenimine mediated magnetite nanoparticles form ordered assembly, in which the resolution of the pattern is doubled. The formation process of ordered structures was systematically investigated. This method is technologically feasible and scalable to make ordered magnetic nanoparticles over a large area. The result of this dissertation demonstrates that polymer stabilizers play an essential role in the synthesis of nanoparticles as well as their assembly.
Author: Bastian Ebeling Publisher: Springer ISBN: 3319152459 Category : Technology & Engineering Languages : en Pages : 311
Book Description
This doctoral thesis explains the synthesis and characterization of novel, smart hybrid nanomaterials. Bastian Ebeling combines in this work synthetic polymers with inorganic nanoparticles from silica or gold. The first chapters offer a comprehensive introduction to basics of polymer science and the applied methodologies. In following chapters, the author describes in detail how he systematically tailored the polymers using reversible addition-fragmentation chain transfer polymerization (RAFT) for combination with inorganic nanoparticles. This work also unravels mechanistic, thermodynamic, and structural aspects of all building blocks and reaction steps. The method described here is simple to perform and opens up pathways to new sets of nanohybrid materials with potential applications as sensors, in energy conversion, or catalysis. Readers will find a unique picture of the step-by step formation of new complex nanomaterials. It offers polymer scientists a systematic guide to the formation and synthesis of a new class of responsive nanomaterials.
Author: Sun Shin Publisher: ISBN: Category : Languages : en Pages :
Book Description
A wide range of molecules, polymers, and particles which possess both hydrophilic and hydrophobic domains are desirable as surface active agents. Unlike their molecular analogs, inorganic nanoparticle (NP) amphiphiles have the ability both to adapt their surface chemistry in response to environmental changes and to respond to external stimuli acting on the particle cores. These unique capabilities enable new strategies for a variety of applications in drug delivery, emulsification, assembly of hierarchical structures, surface coatings, and optoelectronic devices. This dissertation describes experimental methods for preparing and characterizing NP amphiphiles and also discusses their applications in assembly and biomedical engineering.The synthesis of gold NPs functionalized asymmetrically with domains of hydrophobic and hydrophilic ligands on their respective hemispheres is described in Chapter 2. These particle amphiphiles form spontaneously by a thermodynamically controlled process, in which the particle cores and two competing ligands assemble at the interface between two immiscible liquids to reduce the interfacial energy. The asymmetric surface chemistry resulting from this process is confirmed using contact angle measurements of water droplets on NP monolayers deposited onto hydrophobic and hydrophilic substrates. The spontaneous assembly process is rationalized by a thermodynamic model, which accounts both for the energetic contributions driving the assembly and for the entropic penalties that must be overcome. In addition to gold NPs and thiolate ligands, generality of this approach is demonstrated by extending it to the preparation of amphiphilic iron oxide NPs using two types of diol-terminated ligands. The synthetic strategy described here provides a comprehensive solution for designing NP amphiphiles with controlled surface composition and ligand distribution.The self-assembly of gold NP amphiphiles in water is discussed in Chapter 3. Unlike typical amphiphilic particles with "fixed" surface chemistries, the ligands used here are not bound irreversibly but can rearrange dynamically on the particles' surface during their assembly from solution. Depending on the assembly conditions, these adaptive amphiphiles form compact micellar clusters or extended chain-like assemblies in aqueous solution. By controlling the amount of hydrophobic ligands on the particles' surface, the average number of nearest neighbors -- that is, the preferred coordination number -- can be varied systematically from ~1 (dimers) to ~2 (linear chains) to ~3 (extended clusters). To explain these experimental findings, an assembly mechanism is presented in which hydrophobic ligands organize dynamically to form discrete patches between proximal NPs to minimize contact with their aqueous surroundings. Monte Carlo simulations incorporating these adaptive hydrophobic interactions reproduce the three-dimensional assemblies observed in experiment.The spontaneous incorporation of amphiphilic gold NPs into the walls of surfactant vesicles is reported in Chapter 4. When the NP amphiphiles are mixed with preformed surfactant vesicles, the hydrophobic ligands on the NP surface interact favorably with the hydrophobic core of the bilayer structure and guide the incorporation of NPs into the vesicle walls. Unlike previous strategies based on small hydrophobic NPs, the approach described here allows for the incorporation of water soluble particles even when the size of the particles greatly exceeds the bilayer thickness.Finally, a strategy to stabilize open bilayer structures using NP amphiphiles is described in Chapter 5. Molecular amphiphiles self-assemble in polar media to form ordered structures such as micelles and vesicles essential to a broad range of industrial and biological processes. Some of these architectures such as bilayer sheets, helical ribbons, and hollow tubules are potentially useful but inherently unstable owing to the presence of open edges that expose the hydrophobic bilayer core. The particle amphiphiles described here bind selectively to the open edge of bilayer membranes to stabilize otherwise transient amphiphile assemblies. It is demonstrated how such particles can precisely control the size of lipid tubules, how they can inhibit the formation of undesirable assemblies such as gallstone precursors, and how they can stabilize free-floating lipid microdiscs.
Author: Vikas Mittal Publisher: CRC Press ISBN: 1439859787 Category : Technology & Engineering Languages : en Pages : 613
Book Description
Polymer latex particles continue to become increasingly important in numerous commercial applications. Advanced synthesis techniques are the key to developing new functionality for nanoparticles. These methods make it possible to tailor the size, chemical composition, or properties of these particles, as well as the molecular weight of the polymer
Author: STANISLAV. PISPAS RANGELOV (ASTERIOS.) Publisher: CRC Press ISBN: 9780367379568 Category : Languages : en Pages : 499
Book Description
Polymeric and hybrid nanoparticles have received increased scientific interest in terms of basic research as well as commercial applications, promising a variety of uses for nanostructures in fields including bionanotechnology and medicine. Condensing the relevant research into a comprehensive reference, Polymer and Polymer-Hybrid Nanoparticles: From Synthesis to Biomedical Applications covers an array of topics from synthetic procedures and macromolecular design to possible biomedical applications of nanoparticles and materials based on original and unique polymers. The book presents a well-rounded picture of objects ranging from simple polymeric micelles to complex hybrid polymer-based nanostructures, detailing synthetic procedures, techniques for characterization and analysis, properties, and behavior in selective solvents and dispersions. Each chapter contains background and introductory information, summarizing generalities on the nanosystems being discussed. The chapters also describe representative works of experts and provide in-depth, focused discussions. The authors present current knowledge on the following topics: Designed synthesis of functional polymers Construction of block copolymer micellar and nonmicellar self-assembled structures Construction of organic-organic hybrid nanosized particles Construction of organic-inorganic hybrid nanoparticles and nanoassemblies The final chapter addresses biological applications of polymeric nanoparticles, including delivery of low-molecular-weight drugs, macromolecular drugs, imaging and diagnostics, and photodynamic therapy. Summarizing important developments in the field, the authors condense relevant research into a comprehensive resource.
Author: Krzysztof Pielichowski Publisher: Woodhead Publishing ISBN: 0128140658 Category : Technology & Engineering Languages : en Pages : 513
Book Description
Polymer Composites with Functional Nanoparticles: Synthesis, Properties, and Applications reviews the latest research in the area of polymer nanocomposites and functionalized nanoparticles, providing an introduction for those new to the field, and supporting further research and development. The book helps researchers and practitioners better understand the key role of nanoparticle functionalization for improving the compatibility of inorganic metallic nanomaterials with organic polymers, and for the fabrication of nanostructured materials with special properties. A range of nanoparticles, such as carbon nanotubes are covered, along with descriptions of the methods of functionalization to support better compatibility with polymer matrices. The book also discusses the various applications of this technology, including uses in electronics and the medical and energy industries. - Summarizes the latest research in functionalized nanoparticles for modification of polymer matrices, providing a valuable platform for further research - Includes functionalization of a range of nanoparticles for incorporation into nanocomposites, including carbon nanotubes, graphene, gold and silver, silica and clay - Provides detailed coverage of application areas, including energy, electronics, biomedical applications, and end-of-life considerations
Author: Dibyendu Ganguli Publisher: Springer Science & Business Media ISBN: 1461500478 Category : Science Languages : en Pages : 214
Book Description
"Nanotechnology" is now very well known as one of the most important key technologies in science and industry. In the field of material science and engineering, nanoparticles should be unit materials, as well as atoms and molecules, to build ceramics, devices, catalysts, and machines, and the "nanoparticle technology" is thus attracting. This novel technology includes various methodologies for nanoparticles: preparation, surface-modification via chemical and/or physical treatments, immobilization and arrangement on supports or substrates, to achieve high performance for luminescence properties in light emitting devices, and high efficiency for catalytic and photocatalytic reactions in chemical synthesis, chemical decomposition, and artificial photosynthesis, etc. It should be needless to say that the preparation of nanoparticles, having precisely controlled particle size, size distribution, chemical composition, and surface properties, is essentially important to realize "true nanoparticle technology". This book, written by Dr. Dibyendu Ganguli and Dr. Munia Ganguli, deals with the preparation methodologies for inorganic nanoparticles using macro- and microemulsions as "microreactor". There are several differences between these two emulsions, in addition to water droplet size: thermodynamic stability, and fusion-redispersion dynamics of the droplets. The properties of the nanoparticles prepared in these emulsion systems are seriously influenced and controlled by the selection of dynamic and static conditions.
Author: Mingjun Huang Publisher: ISBN: Category : Amphiphiles Languages : en Pages : 220
Book Description
"Bottom-up" techniques-based self-assembly are always attracting people's interests since this technology provides relatively low economic cost and fast route to construct organized structures at different scales. Considering unprecedented benefits from polymer materials, self-assemblies utilizing polymer building blocks have been extensively studied to achieve diverse hierarchical structures and various attractive properties. However, precise controls of chemical primary structures and compositions and exact constructions of hierarchal ordered structures in synthetic polymers are far from being fully appreciated. In this dissertation, a novel approach has been utilized to construct diverse well-defined nano-building blocks, giant molecules, via conjugating different, and functionalized molecular nanoparticles (MNPs) which are shape- and volume-persistent nano-objects with precise molecular structure and specific symmetry. The representative examples of the three basic categories of giant molecules, "giant polyhedra", "giant surfactants", and "giant shape amphiphiles" were discussed in details. First, a class of precisely defined, nanosized giant tetrahedra was constructed by placing different polyhedral oligomeric silsesquioxane (POSS) molecular nanoparticles at the vertices of a rigid tetrahedral framework. Designed symmetry breaking of these giant tetrahedra introduces accurate positional interactions and results in diverse selectively assembled, highly ordered supramolecular lattices including a Frank-Kasper (FK) A15 phase. The FK and quasicrystal phases are originally identified in metal alloys and only sporadically observed in soft matters. It remains unclear how to correlate their stability with the chemical composition and molecular topology in the self-assembling systems. We then for this purpose designed and studied the self-assembly phase transition sequences of four series of hybrid giant surfactants based on hydrophilic POSS cages tethered with one to four polystyrene (PS) tails. With increasing the number of tails, molecular topological variations not only affect phase boundaries in terms of the PS volume fraction, but also open a window to stabilize supramolecular FK and quasicrystal phases in the spherical phase region, demonstrating the critical role of molecular topology in dictating the formation of unconventional supramolecular lattices of "soft" spherical motifs. The FK A15 phase was even surprisingly observed in the giant shape amphiphile molecule, triphenylene-6BPOSS, which has a disk-like flat triphenylene core connected with six hydrophobic POSS cages by sides. Without conical molecular shape, triphenylene-6BPOSS self-assembled and stabilized into supramolecular sphere via p-p interactions through a completely different mechanism with precious two cases. These studies indicate that "bottom-up" self-assemble based on well-defined giant molecules approach can be rather powerful to fabricate usually complicated hierarchical structures and open up a wide field of supramolecular self-assembly with unexpected structure and properties.
Author: Brian Coleman
Author: Brian Coleman
Author: José A. Pomposo
Author: Litao Bai
Author: Bastian Ebeling
Author: Sun Shin
Author: Vikas Mittal
Author: STANISLAV. PISPAS RANGELOV (ASTERIOS.)
Author: Krzysztof Pielichowski
Author: Dibyendu Ganguli
Author: Mingjun Huang