Download or read book Amphiphilic Block Copolymer Synthesis Via RAFT Polymerization and Their Self assembly Behavior written by Wei Zhao and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Amphiphilic Polymer Co networks written by Costas S Patrickios and published by Royal Society of Chemistry. This book was released on 2020-04-23 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amphiphilic polymer co-networks (APCNs) are a type of polymeric hydrogel, their hydrophobic polymer segments and hydrophilic components produce less aqueous swelling, giving better mechanical properties than conventional hydrogels. This new class of polymers is attracting increasing attention, resulting in further basic research on the system, as well as new applications. This book focuses on new developments in the field of APCNs, and is organised in four sections: synthesis, properties, applications and modelling. Co-network architectures included in the book chapters are mainly those deriving from hydrophobic macro-cross-linkers, representing the classical approach; however, more modern designs are also presented. Properties of interest discussed include aqueous swelling, thermophysical and mechanical properties, self-assembly, electrical actuation, and protein adsorption. Applications described in the book chapters include the use of co-networks as soft contact lenses, scaffolds for drug delivery and tissue engineering, matrices for heterogeneous biocatalysis, and membranes of controllable permeability. Finally, an important theory chapter on the modelling of the self-assembly of APCNs is also included. The book is suitable for graduate students and researchers interested in hydrogels, polymer networks, polymer chemistry, block copolymers, self-assembly and nanomaterials, as well as their applications in contact lenses, drug delivery, tissue engineering, membranes and biocatalysis.

Download or read book Synthesis and Solution Self Assembly of Poly L Lactide Based Amphiphilic Block Copolymers written by Amy Petretic and published by . This book was released on 2015 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Amphiphilic Block Copolymers written by P. Alexandridis and published by Elsevier. This book was released on 2000-10-18 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Synthesis and Self assembly of Multiple Thermoresponsive Amphiphilic Block Copolymers written by Jan Weiss and published by . This book was released on 2011 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the present thesis, the self-assembly of multi thermoresponsive block copolymers in dilute aqueous solution was investigated by a combination of turbidimetry, dynamic light scattering, TEM measurements, NMR as well as fluorescence spectroscopy. The successive conversion of such block copolymers from a hydrophilic into a hydrophobic state includes intermediate amphiphilic states with a variable hydrophilic-to-lipophilic balance. As a result, the self-organization is not following an all-or-none principle but a multistep aggregation in dilute solution was observed. The synthesis of double thermoresponsive diblock copolymers as well as triple thermoresponsive triblock copolymers was realized using twofold-TMS labeled RAFT agents which provide direct information about the average molar mass as well as residual end group functionality from a routine proton NMR spectrum. First a set of double thermosensitive diblock copolymers poly(N-n-propylacrylamide)-b-poly(N-ethylacrylamide) was synthesized which differed only in the relative size of the two blocks. Depending on the relative block lengths, different aggregation pathways were found. Furthermore, the complementary TMS-labeled end groups served as NMR-probes for the self-assembly of these diblock copolymers in dilute solution. Reversible, temperature sensitive peak splitting of the TMS-signals in NMR spectroscopy was indicative for the formation of mixed star-/flower-like micelles in some cases. Moreover, triple thermoresponsive triblock copolymers from poly(N-n-propylacrylamide) (A), poly(methoxydiethylene glycol acrylate) (B) and poly(N-ethylacrylamide) (C) were obtained from sequential RAFT polymerization in all possible block sequences (ABC, BAC, ACB). Their self-organization behavior in dilute aqueous solution was found to be rather complex and dependent on the positioning of the different blocks within the terpolymers. Especially the localization of the low-LCST block (A) had a large influence on the aggregation behavior. Above the first cloud point, aggregates were only observed when the A block was located at one terminus. Once placed in the middle, unimolecular micelles were observed which showed aggregation only above the second phase transition temperature of the B block. Carrier abilities of such triple thermosensitive triblock copolymers tested in fluorescence spectroscopy, using the solvatochromic dye Nile Red, suggested that the hydrophobic probe is less efficiently incorporated by the polymer with the BAC sequence as compared to ABC or ACB polymers above the first phase transition temperature. In addition, due to the problem of increasing loss of end group functionality during the subsequent polymerization steps, a novel concept for the one-step synthesis of multi thermoresponsive block copolymers was developed. This allowed to synthesize double thermoresponsive di- and triblock copolymers in a single polymerization step. The copolymerization of different N-substituted maleimides with a thermosensitive styrene derivative (4-vinylbenzyl methoxytetrakis(oxyethylene) ether) led to alternating copolymers with variable LCST. Consequently, an excess of this styrene-based monomer allowed the synthesis of double thermoresponsive tapered block copolymers in a single polymerization step.

Download or read book Aqueous RAFT Synthesis of Stimuli responsive Amphiphilic Block Copolymers and Self assembly Behavior in Solution and Incorporation Into LBL Films written by Matthew Grady Kellum and published by . This book was released on 2010 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis Characterization and Self assembly of Amphiphilic Block Copolymers written by Xiaojun Wang and published by . This book was released on 2012 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a review on state-of-the-art research of well-defined charged block copolymers, including synthesis, characterization, bulk morphology and self-assembly in aqueous solution of amphiphilic block polyelectrolytes. In Chapter 1, as a general introduction, experimental observations and theoretical calculations devoted towards understanding morphological behavior in charged block copolymer systems are reviewed along with some of the new emerging research directions. Further investigation of charged systems is urged in order to fully understand their morphological behavior and to directly target structures for the tremendous potential in technological applications. Following this background, in Chapters 2, 3, 4 and 5 are presented the design and synthesis of a series of well-defined block copolymers composed of charged and neutral block copolymers with full characterization: sulfonated polystyrene-b-fluorinated polyisoprene (sPS-b-fPI) and polystyrene-b-sulfonated poly(1,3-cyclohexadiene) (PS-b-sPCHD). Their bulk morphological behaviors in melts and self-assembly of sPS-b-fPI, PS-b-sPCHD in water were investigated. Some unique behaviors of sPS-b-fPI were discovered. The mechanisms for formation of novel nanostructures in aqueous solution are discussed in details in Chapter 4. Spherical and vesicular structures were formed from strong electrolyte block copolymers, e.g. PS-bsPCHD. Detailed light scattering and transmission electron microscopy were applied to characterize these structures. The abnormal formation of vesicles as well as microstructure effects on self-assembly is discussed in Chapter 5. In Chapter 6, we describe the successful synthesis of a well-defined acid-based block copolymers containing polyisoprene while maintaining the integrity of the functionality (double bonds) of polyisoprene. A general purification method is also presented in order to remove homo polyisoprene, polystyrene, and PS-b-PI in the di-, and tri-block copolymers. The self-assembly of PS-b-PI-b-PAA triblock terpolymers was studied in order to form multicompartmental structures in aqueous environments. In the last Chapter 7, detailed synthesis and characterization of a novel conjugate: poly(L-leucine) grafted hyaluronan (HA) (HA-g-PLeu) are presented. This work describes a new method to synthesize HA-g-PLeu via a "grafting onto" strategy. Due to the amphiphilic nature of this graft copolymers, a "local network" formed by self-assembly which was characterized by atomic force microscopy and light scattering. The secondary structure of the polypeptide was revealed by circular dichroism.

Download or read book Glycopolymer Code written by C. Remzi Becer and published by Royal Society of Chemistry. This book was released on 2015-03-23 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glycopolymers are important for cell signalling, recognition pathways, and their role in the immune system. They are gaining attention for new applications in tissue engineering and drug delivery. Glycopolymer Code discusses the preparation, characterization and applications of glycopolymers providing a complete overview of the topic with examples from the latest research. Specific chapters cover both basic and advanced synthesis techniques to prepare glycopolymers, the analytical techniques used to investigate lectin receptor glycopolymer interactions, the properties and types of lectins that are widely used to understand the multivalent interactions and various applications of synthetic glycopolymers. With contributions from leading researchers in the field, the book is a unique source for graduates and academics new to the subject and already working in the area of glycopolymers.

Download or read book Self assembly Behavior in Hydrophilic Block Copolymers written by Clara Valverde Serrano and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymers are receiving increasing attention in the literature. Reports on amphiphilic block copolymers have now established the basis of their self-assembly behavior: aggregate sizes, morphologies and stability can be explained from the absolute and relative block lengths, the nature of the blocks, the architecture and also solvent selectiveness. In water, self-assembly of amphiphilic block copolymers is assumed to be driven by the hydrophobic. The motivation of this thesis is to study the influence on the self-assembly in water of A b B type block copolymers (with A hydrophilic) of the variation of the hydrophilicity of B from non-soluble (hydrophobic) to totally soluble (hydrophilic). Glucose-modified polybutadiene-block-poly(N-isopropylacrylamide) copolymers were prepared and their self-assembly behavior in water studied. The copolymers formed vesicles with an asymmetric membrane with a glycosylated exterior and poly(N-isopropylacrylamide) on the inside. Above the low critical solution temperature (LCST) of poly(N-isopropylacrylamide), the structure collapsed into micelles with a hydrophobic PNIPAM core and glycosylated exterior. This collapse was found to be reversible. As a result, the structures showed a temperature-dependent interaction with L-lectin proteins and were shown to be able to encapsulate organic molecules. Several families of double hydrophilic block copolymers (DHBC) were prepared. The blocks of these copolymers were biopolymers or polymer chimeras used in aqueous two-phase partition systems. Copolymers based on dextran and poly(ethylene glycol) blocks were able to form aggregates in water. Dex6500-b-PEG5500 copolymer spontaneously formed vesicles with PEG as the "less hydrophilic" barrier and dextran as the solubilizing block. The aggregates were found to be insensitive to the polymer's architecture and concentration (in the dilute range) and only mildly sensitive to temperature. Variation of the block length, yielded different morphologies. A longer PEG chain seemed to promote more curved aggregates following the inverse trend usually observed in amphiphilic block copolymers. A shorter dextran promoted vesicular structures as usually observed for the amphiphilic counterparts. The linking function was shown to have an influence of the morphology but not on the self-assembly capability in itself. The vesicles formed by dex6500-b-PEG5500 showed slow kinetics of clustering in the presence of Con A lectin. In addition both dex6500-b-PEG5500 and its crosslinked derivative were able to encapsulate fluorescent dyes. Two additional dextran-based copolymers were synthesized, dextran-b-poly(vinyl alcohol) and dextran-b-poly(vinyl pyrrolidone). The study of their self-assembly allowed to conclude that aqueous two-phase systems (ATPS) is a valid source of inspiration to conceive DHBCs capable of self-assembling. In the second part the principle was extended to polypeptide systems with the synthesis of a poly(N-hydroxyethylglutamine)-block-poly(ethylene glycol) copolymer. The copolymer that had been previously reported to have emulsifying properties was able to form vesicles by direct dissolution of the solid in water. Last, a series of thermoresponsive copolymers were prepared, dextran-b-PNIPAMm. These polymers formed aggregates below the LCST. Their structure could not be unambiguously elucidated but seemed to correspond to vesicles. Above the LCST, the collapse of the PNIPAM chains induced the formation of stable objects of several hundreds of nanometers in radius that evolved with increasing temperature. The cooling of these solution below LCST restored the initial aggregates. This self-assembly of DHBC outside any stimuli of pH, ionic strength, or temperature has only rarely been described in the literature. This work constituted the first formal attempt to frame the phenomenon. Two reasons were accounted for the self-assembly of such systems: incompatibility of the polymer pairs forming the two blocks (enthalpic) and a considerable solubility difference (enthalpic and entropic). The entropic contribution to the positive Gibbs free energy of mixing is believed to arise from the same loss of conformational entropy that is responsible for "the hydrophobic effect" but driven by a competition for water of the two blocks. In that sense this phenomenon should be described as the "hydrophilic effect".

Download or read book Amphiphilic Block Copolymers written by Tiambo Liu and published by . This book was released on 1999 with total page 888 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Synthesis and Characterization of Amphiphilic Poly ethylene Oxide block poly octadecyl Acrylate Block Copolymers written by Yi Wang (Polymer engineer) and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of well-defined poly(ethylene oxide)-block-poly(octadecyl acrylate) (PEO-b-PODA) diblock copolymers were successfully synthesized by reversible addition fragmentation transfer (RAFT) polymerization with low polydispersities (M[subscript w]/M[subscript n] = 1.09-1.13). The crystallization behavior of poly(ethylene oxide)-block-poly(octadecyl acrylate) (PEO-b-PODA) diblock copolymers has been studied by differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS) and polarized optical microscopy (POM). The melt morphology of PEO455-PODA19 experienced a transition from lamella to cylinder at 130°C. For the double crystalline block copolymer PEO455-PODA19, the micro-phase separation at 55°C created lamellar micro-domains, which confined the PEO blocks as it crystallized. The leading crystallization of PEO blocks then created a space that confined PODA crystallites as they are developed. The spherulites were formed first when PEO started to crystallize, but crystallites with polyhedral shape finally formed. As for the micelle behavior, the transmission electron microscopy (TEM) showed that amphiphilic block copolymers PEO-PODA with different volume fractions of hydrophobic PODA blocks ranging from 21% to 54%, were able to self-assemble in water forming spherical micelles.

Download or read book The Synthesis and Self assembly of MPC Block Copolymers written by Lauren Cowie and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Biocompatible and biodegradable poly(lactide)-2-methacryloyloxyethyl phosphorylcholine (PLA-PMPC) amphiphilic block copolymers were synthesized by a combination of Ring Opening Polymerization (ROP) and Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization techniques. The PLA-macroRAFT agent was synthesized by the derivatization of PLA-OH with RAFT agent 4-cyano-4-(phenylcarbonothioylthio)pentanoic acid (CPADB) achieving high levels of functionalization and narrow weight distributions (PDI range of 1.02-1.17). PLA-PMPC with varied MPC block lengths were synthesized yielding polymers with a narrow polydispersity PDI = 1.16-1.21. Triblock copolymers PMPC-PLA-PMPC with varying hydrophilic weight ratios were synthesized following an analogous method, the polymerizations were shown to be controlled with PDI's of 1.24 and 1.36. PLA-PMPC block copolymers with varied compositions were self-assembled using several techniques to target different morphologies. Nanostructures were characterised by DLS and TEM. Block copolymers with a larger PLA block length were shown to generate smaller aggregates i.e. micelles. The morphologies observed for the various block copolymers were consistent amongst different preparative techniques. Vesicle structures were reproducible by the self-assembly of PMPC50-PLA51-PMPC50, however, by preparing nanoparticles by direct dissolution micelles formed. The block copolymers were shown to encapsulate a hydrophobic dye in aqueous media thereby demonstrating its potential drug delivery applications.

Download or read book Synthesis and Characterization of Smart Block Copolymers for Biomineralization and Biomedical Applications written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-assembly is a powerful tool in forming structures with nanoscale dimensions. Self-assembly of macromolecules provides an efficient and rapid pathway for the formation of structures from the nanometer to micrometer range that are difficult, if not impossible to obtain by conventional lithographic techniques [1]. Depending on the morphologies obtained (size, shape, periodicity, etc.) these self-assembled systems have already been applied or shown to be useful for a number of applications in nanotechnology [2], biomineralization [3, 4], drug delivery [5, 6] and gene therapy [7]. In this respect, amphiphilic block copolymers that self-organize in solution have been found to be very versatile [1]. In recent years, polymer-micellar systems have been designed that are adaptable to their environment and able to respond in a controlled manner to external stimuli. In short, synthesis of 'nanoscale objects' that exhibit 'stimulus-responsive' properties is a topic gathering momentum, because their behavior is reminiscent of that exhibited by proteins [8]. By integrating environmentally sensitive homopolymers into amphiphilic block copolymers, smart block copolymers with self assembled supramolecular structures that exhibit stimuli or environmentally responsive properties can be obtained [1]. Several synthetic polymers are known to have environmentally responsive properties. Changes in the physical, chemical or biochemical environment of these polymers results in modulation of the solubility or chain conformation of the polymer [9]. There are many common schemes of engineering stimuli responsive properties into materials [8, 9]. Polymers exhibiting lower critical solution temperature (LCST) are soluble in solvent below a specific temperature and phase separate from solvent above that temperature while polymers exhibiting upper critical solution temperatures (UCST) phase separate below a certain temperature. The solubility of polymers with ionizable moieties depends on the pH of the solution. Polymers with polyzwitterions, anions and cations have been shown to exhibit pH responsive self assembly. Other stimuli responsive polymers include glucose sensitive polymers, calcium ion-sensitive polymers and so on. Progress in living radical polymerization (LRP) methods [10] has made it possible for the facile synthesis of these block copolymer systems with controlled molecular weights and well defined architectures. The overall theme of this work is to develop novel smart block copolymers for biomineralization and biomedical applications. Synthesis and characterization of self-assembling thermoreversible ionic block copolymers as templates in biomimetic nanocomposite synthesis using a bottom-up approach is a novel contribution in this respect. Further, we have extended these families of copolymers to include block copolymer-peptide conjugates to enhance biological specificity. Future directions on this work will focus on enhancing the polymer templating properties for biomineralization by expanding the family of block copolymers with organic polypeptides and biological polypeptide scaffolds as well as a detailed understanding of the polymer-inorganic nanocomposites at the molecular level using small angle scattering analysis. Glucose responsive polymer hydrogels for drug delivery, polymer-ligand conjugates for non-viral therapy and thermoresponsive injectable photocrosslinkable hydrogels for posttraumatic arthritis cartilage healing are other applications of these novel copolymers synthesized in our work.

Download or read book Synthesis and Applications of Copolymers written by Anbanandam Parthiban and published by John Wiley & Sons. This book was released on 2014-06-23 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the reactivity of monomers is crucial in creating copolymers and determining the outcome of copolymerization. Covering the fundamental aspects of polymerization, Synthesis and Applications of Copolymers explores the reactivity of monomers and reaction conditions that ensure that the newly formed polymeric materials exhibit desired properties. Referencing a wide-range of disciplines, the book provides researchers, students, and scientists with the preparation of a diverse variety of copolymers and their recent developments, with a particular focus on copolymerization, crystallization, and techniques like nanoimprinting and micropatterning.

Download or read book Poly lactide based Amphiphilic Block Copolymers written by Sebastian Noack and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to its bioavailability and (bio)degradability, poly(lactide) (PLA) is an interesting polymer that is already being used as packaging material, surgical seam, and drug delivery system. Dependent on various parameters such as polymer composition, amphiphilicity, sample preparation, and the enantiomeric purity of lactide, PLA in an amphiphilic block copolymer can affect the self-assembly behavior dramatically. However, sizes and shapes of aggregates have a critical effect on the interactions between biological and drug delivery systems, where the general understanding of these polymers and their ability to influence self-assembly is of significant interest in science. The first part of this thesis describes the synthesis and study of a series of linear poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA)-based amphiphilic block copolymers with varying PLA (hydrophobic), and poly(ethylene glycol) (PEG) (hydrophilic) chain lengths and different block copolymer sequences (PEG-PLA and PLA-PEG). ...

Download or read book Synthesis and Characterization of Well defined Amphiphilic Ionic Copolymers written by Yuqing Liu (Polymer engineer) and published by . This book was released on 2011 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Amphiphilic ionic block copolymers are promising materials for the fabrication of ion-exchange membranes in fuel cells, water purification and advanced molecular engineering applications, such as nanotemplating. For example, block copolymer architectures provide a route to fabricate membranes with tunable transport properties through polymer self assembly. A significant challenge in this field is the synthesis of amphiphilic copolymers, where the intrinsic immiscibility of the hydrophobic and hydrophilic monomers complicates polymerization. To address the immiscibility between sodium p-styrenesulfonate and styrene monomers, styrenesulfonate monomers were neutralized by hydrophobic trialkyl ammonium salts via ion-exchange reactions, and synthesized successfully by RAFT polymerization with low polydispersity (PDI). Diblock or triblock copolymers with well-defined architectures were obtained by sequential RAFT polymerization with styrene. These sulfonate groups were then converted to the sodium salt form via ion-exchange to obtain amphiphilic ionic block copolymers. It was observed that dimethyl n-alkyl ammonium salts of polystyrenesulfonate displayed thermo-reversible gelation behavior in low polarity organic solvents. The investigation of the gelation behavior as a function of temperature, concentration, and solvent was consistent with gelation driven by the ionic aggregation of the polymer as would be expected for polyelectrolyte surfactant complexes in non-polar solvents. Cationic amphiphilic block/graft copolymers containing quaternary ammonium salts were prepared by the RAFT polymerization of polystyrene-b-poly(vinylbenzyl chloride) (PS-b-PVBC) copolymers, and sequential post-polymerization quaternization of the PVBC blocks. PS-b-PVBEA-b-PS triblock copolymers with well-defined architectures were obtained and the ion conductivity of the corresponding membranes, as well as the morphology of the membranes, was investigated. To improve the mechanical properties of the membranes, different architectures, such as pentablock, heptablock and graft copolymers, were designed and synthesized by RAFT polymerization, and chemical crosslinking was employed to improve the mechanical properties and control the swelling in water. Lastly, a new method to prepare multiblock copolymers via a facile route was developed. Polytrithiocarbonates were prepared by condensation polymerization of a dicarboxylic acid functional trithiocarbonate and a diol, and the trithiocarbonate group was controlled by tuning the amount of acid catalyst and reaction time. The polytrithiocarbonate RAFT agents were used to polymerize PS, polystyrene-b-poly (tert-butylstyrene) (PS-b-PtBS), and PS-b-PVBC. The PDI of the polymers toward 2, but the PDI of the polymer blocks between two trithiocarbonate groups was narrow (1.1-1.3 for PS and PS-b-PtBS, and 1.46 for PS-b-PVBC). The PVBC segments were quaternized to achieve anionic amphiphilic multiblock copolymers.

Download or read book New Hydrogel Forming Thermo responsive Block Copolymers of Increasing Structural Complexity written by Anna Miasnikova and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work describes the synthesis and characterization of stimuli-responsive polymers made by reversible addition-fragmentation chain transfer (RAFT) polymerization and the investigation of their self-assembly into "smart" hydrogels. In particular the hydrogels were designed to swell at low temperature and could be reversibly switched to a collapsed hydrophobic state by rising the temperature. Starting from two constituents, a short permanently hydrophobic polystyrene (PS) block and a thermo-responsive poly(methoxy diethylene glycol acrylate) (PMDEGA) block, various gelation behaviors and switching temperatures were achieved. New RAFT agents bearing tert-butyl benzoate or benzoic acid groups, were developed for the synthesis of diblock, symmetrical triblock and 3-arm star block copolymers. Thus, specific end groups were attached to the polymers that facilitate efficient macromolecular characterization, e.g by routine 1H-NMR spectroscopy. Further, the carboxyl end-groups allowed functionalizing the various polymers by a fluorophore. Because reports on PMDEGA have been extremely rare, at first, the thermo-responsive behavior of the polymer was investigated and the influence of factors such as molar mass, nature of the end-groups, and architecture, was studied. The use of special RAFT agents enabled the design of polymer with specific hydrophobic and hydrophilic end-groups. Cloud points (CP) of the polymers proved to be sensitive to all molecular variables studied, namely molar mass, nature and number of the end-groups, up to relatively high molar masses. Thus, by changing molecular parameters, CPs of the PMDEGA could be easily adjusted within the physiological interesting range of 20 to 40°C. A second responsivity, namely to light, was added to the PMDEGA system via random copolymerization of MDEGA with a specifically designed photo-switchable azobenzene acrylate. The composition of the copolymers was varied in order to determine the optimal conditions for an isothermal cloud point variation triggered by light. Though reversible light-induced solubility changes were achieved, the differences between the cloud points before and after the irradiation were small. Remarkably, the response to light differed from common observations for azobenzene-based systems, as CPs decreased after UV-irradiation, i.e with increasing content of cis-azobenzene units. The viscosifying and gelling abilities of the various block copolymers made from PS and PMDEGA blocks were studied by rheology. Important differences were observed between diblock copolymers, containing one hydrophobic PS block only, the telechelic symmetrical triblock copolymers made of two associating PS termini, and the star block copolymers having three associating end blocks. Regardless of their hydrophilic block length, diblock copolymers PS11 PMDEGAn were freely flowing even at concentrations as high as 40 wt. %. In contrast, all studied symmetrical triblock copolymers PS8-PMDEGAn-PS8 formed gels at low temperatures and at concentrations as low as 3.5 wt. % at best. When heated, these gels underwent a gel-sol transition at intermediate temperatures, well below the cloud point where phase separation occurs. The gel-sol transition shifted to markedly higher transition temperatures with increasing length of the hydrophilic inner block. This effect increased also with the number of arms, and with the length of the hydrophobic end blocks. The mechanical properties of the gels were significantly altered at the cloud point and liquid-like dispersions were formed. These could be reversibly transformed into hydrogels by cooling. This thesis demonstrates that high molar mass PMDEGA is an easily accessible, presumably also biocompatible and at ambient temperature well water-soluble, non-ionic thermo-responsive polymer. PMDEGA can be easily molecularly engineered via the RAFT method, implementing defined end-groups, and producing different, also complex, architectures, such as amphiphilic triblock and star block copolymers, having an analogous structure to associative telechelics. With appropriate design, such amphiphilic copolymers give way to efficient, "smart" viscosifiers and gelators displaying tunable gelling and mechanical properties.