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Author: Joe Chih-Wei Wang Publisher: ISBN: Category : Languages : en Pages :
Book Description
The self-assembly of polystyrene-stabilized cadmium sulfide nanoparticles (PS-CdS) with amphiphilic stabilizing chains of polystyrene-block-poly(acrylic acid) (PS-b-PAA) into colloidal quantum dot compound micelles (QDCMs) is studied on two-phase gas-liquid segmented microfluidic reactors. The resulting particle sizes are found to arise from the interplay of shear-induced coalescence and particle breakup, depending on a combination of chemical and flow conditions. Variation of water content, gas-to-liquid ratio, and total flow rate, enable control of QDCM sizes in the range of 140? 40 nm. The flow-variable shear effect on similar microfluidic reactors is then applied to direct the solution self-assembly of a PS-b-PAA block copolymer into various micelle morphologies. The difference between off-chip and on-chip morphologies under identical chemical conditions is explained by a mechanism of shear-induced coalescence enabled by strong and localized on-chip shear fields, followed by intraparticle chain rearrangements to minimize local free energies. Time-dependent studies of these nanostructures reveal that on-chip kinetic structures will relax to global equilibrium given sufficient time off-chip. Further investigations into the effect of chemical variables on on-chip shear-induced morphologies reveal a combination of thermodynamic and kinetic effects, opening avenues for morphology control via combined chemical (bottom-up) and shear (top-down) forces. An equilibrium phase diagram of off-chip micelle morphologies is constructed and used in conjunction with kinetic considerations to rationalize on-chip mechanisms and morphologies, including cylinders and vesicles, under different chemical conditions. Finally, we extend our strategy of two-phase microfluidic self-assembly of PS-b-PAA to the loading of fluorescent hydrophobic probes (pyrene and naphthalene) with different affinities for the PS core. The on-chip loading approach provides a fast alternate to the slow off-chip method, with implications for the potential development for point-of-care devices for drug loading. On-chip loading results indicate that loading efficiencies are dependent on water content and, to a lesser extent, on flow rate; the results also suggest that the on-chip morphologies of the PS-b-PAA micelles are an important factor in the loading efficiencies.
Author: Joe Chih-Wei Wang Publisher: ISBN: Category : Languages : en Pages :
Book Description
The self-assembly of polystyrene-stabilized cadmium sulfide nanoparticles (PS-CdS) with amphiphilic stabilizing chains of polystyrene-block-poly(acrylic acid) (PS-b-PAA) into colloidal quantum dot compound micelles (QDCMs) is studied on two-phase gas-liquid segmented microfluidic reactors. The resulting particle sizes are found to arise from the interplay of shear-induced coalescence and particle breakup, depending on a combination of chemical and flow conditions. Variation of water content, gas-to-liquid ratio, and total flow rate, enable control of QDCM sizes in the range of 140? 40 nm. The flow-variable shear effect on similar microfluidic reactors is then applied to direct the solution self-assembly of a PS-b-PAA block copolymer into various micelle morphologies. The difference between off-chip and on-chip morphologies under identical chemical conditions is explained by a mechanism of shear-induced coalescence enabled by strong and localized on-chip shear fields, followed by intraparticle chain rearrangements to minimize local free energies. Time-dependent studies of these nanostructures reveal that on-chip kinetic structures will relax to global equilibrium given sufficient time off-chip. Further investigations into the effect of chemical variables on on-chip shear-induced morphologies reveal a combination of thermodynamic and kinetic effects, opening avenues for morphology control via combined chemical (bottom-up) and shear (top-down) forces. An equilibrium phase diagram of off-chip micelle morphologies is constructed and used in conjunction with kinetic considerations to rationalize on-chip mechanisms and morphologies, including cylinders and vesicles, under different chemical conditions. Finally, we extend our strategy of two-phase microfluidic self-assembly of PS-b-PAA to the loading of fluorescent hydrophobic probes (pyrene and naphthalene) with different affinities for the PS core. The on-chip loading approach provides a fast alternate to the slow off-chip method, with implications for the potential development for point-of-care devices for drug loading. On-chip loading results indicate that loading efficiencies are dependent on water content and, to a lesser extent, on flow rate; the results also suggest that the on-chip morphologies of the PS-b-PAA micelles are an important factor in the loading efficiencies.
Author: P. Alexandridis Publisher: Elsevier ISBN: 0080527108 Category : Science Languages : en Pages : 449
Book Description
It is the belief of the editors of this book that the recognition of block copolymers as being amphiphilic molecules and sharing common features with other well-studied amphiphiles will prove beneficial to both the surfactant and the polymer communities. An aim of this book is to bridge the two communities and cross-fertilise the different fields. To this end, leading researchers in the field of amphiphilic block copolymer self-assembly, some having a background in surfactant chemistry, and others with polymer physics roots, have agreed to join forces and contribute to this book.The book consists of four entities. The first part discusses theoretical considerations behind the block copolymer self-assembly in solution and in the melt. The second part provides case studies of self-assembly in different classes of block copolymers (e.g., polyethers, polyelectrolytes) and in different environments (e.g., in water, in non-aqueous solvents, or in the absence of solvents). The third part presents experimental tools, ranging from static (e.g., small angle neutron scattering) to dynamic (e.g., rheology), which can prove valuable in the characterization of block copolymer self-assemblies. The fourth part offers a sampling of current applications of block copolymers in, e.g., formulations, pharmaceutics, and separations, applications which are based on the unique self-assembly properties of block copolymers.
Author: Li-Chen Cheng (Ph.D.) Publisher: ISBN: Category : Languages : en Pages : 188
Book Description
Self-assembly of block copolymers (BCPs) is emerging as a promising route for numerous technological applications to fabricate a variety of nanoscopic structures. The resulting feature sizes range from a few to several hundred nanometers, and are readily tunable by varying the molecular weights of block copolymers. Directed self-assembly of block copolymer is an effective way to pattern periodic arrays of features with long-range order, to generate complex patterns, and to multiplicatively increase the pattern density and resolution that are far beyond the limit of conventional lithography. Despite of the significant progress in the area of directed self-assembly in recent years, critical research problems regarding the dimension scalability toward sub-10-nm regime and large feature sizes on hundreds of nanometers scale as well as the capability of generating complex device-oriented patterns remain challenging. In this thesis, BCP systems, including high-v BCPs that are capable of self-assembling into extreme small and large feature sizes as well as those with more complex block architectures, are identified and studied in order to understand how those materials may be processed and directed selfassembly to bridge the patterning size spectrum between nano- and micro-fabrication. Another focus is placed on the scientific exploration of directed self-assembly of triblock terpolymers and the investigation on the mechanisms that regulate the scaling and geometry of self-assembled patterns. A comprehensive understanding about self-assembly of BCP thin films will enable developing device-oriented geometries, manipulating BCPs phase behavior, and incorporating new functional materials for a wider range of applications. In the meanwhile, optimizing the processing condition of self-assembly of various BCPs is essential to confirm viability of the directed self-assembly of block copolymers process in manufacturing.
Author: Ian W. Hamley Publisher: John Wiley & Sons ISBN: Category : Science Languages : en Pages : 312
Book Description
This unique text discusses the solution self-assembly of block copolymers and covers all aspects from basic physical chemistry to applications in soft nanotechnology. Recent advances have enabled the preparation of new materials with novel self-assembling structures, functionality and responsiveness and there have also been concomitant advances in theory and modelling. The present text covers the principles of self-assembly in both dilute and concentrated solution, for example micellization and mesophase formation, etc., in chapters 2 and 3 respectively. Chapter 4 covers polyelectrolyte block copolymers - these materials are attracting significant attention from researchers and a solid basis for understanding their physical chemistry is emerging, and this is discussed. The next chapter discusses adsorption of block copolymers from solution at liquid and solid interfaces. The concluding chapter presents a discussion of selected applications, focussing on several important new concepts. The book is aimed at researchers in polymer science as well as industrial scientists involved in the polymer and coatings industries. It will also be of interest to scientists working in soft matter self-assembly and self-organizing polymers.
Author: Aparna Thankappan Publisher: CRC Press ISBN: 1351376365 Category : Technology & Engineering Languages : en Pages : 380
Book Description
This volume provides in-depth knowledge and recent research on polymers and nanostructured materials from synthesis to advanced applications. Leading researchers from industry, academia, government, and private research institutions across the globe have contributed to this volume, covering new research on nanocomposites, polymer technology, and electrochemistry.
Author: Gerardo Perozziello Publisher: Elsevier ISBN: 0128224975 Category : Technology & Engineering Languages : en Pages : 433
Book Description
Microfluidics for Cellular Applications describes microfluidic devices for cell screening from a physical, technological and applications point-of-view, presenting a comparison with the cell microenvironment and conventional instruments used in medicine. Microfluidic technologies, protocols, devices for cell screening and treatment have reached an advanced state but are mainly used in research. Sections break them down into practical applications and conventional medical procedures and offers insights and analysis on how higher resolutions and fast operations can be reached. This is an important resource for those from an engineering and technology background who want to understand more and gain additional insights on cell screening processes. - Outlines the major applications of microfluidic devices in medicine and biotechnology - Assesses the major challenges of using microfluidic devices in terms of complexity of the control set-up, ease of use, integration capability, automation level, analysis throughput, content and costs - Describes the major fabrication techniques for assembling effective microfluidic devices for bioapplications
Author: Joe Chih-Wei Wang
Author: Joe Chih-Wei Wang
Author: P. Alexandridis
Author: Li-Chen Cheng (Ph.D.)
Author: Ian W. Hamley
Author: Mark P. Stoykovich
Author: Kathleen A. Cogan
Author: Nitin Sharma
Author: Aparna Thankappan
Author: Gerardo Perozziello
Author: Adam M. Welander