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Triblock Copolymers

Hirokazu Maruoka, Atsuko Tomita, Zheng Liu, Tatsuo Kimura
Considering the closed packing of supramolecular mediated cage-type (spherical) mesopores inside spherical particles that are typically obtained by the aerosol-assisted process, uniform mesopores cannot be packed so periodically and then the mesopores are less connected and/or occasionally isolated, leading to the formation of low-surface-area mesoporous particles. In this study, we proposed the controlled swelling of such cage-type mesopores for improving their connectivity. Actually, we succeeded in preparing high-surface-area mesoporous alumina powders using poly(oxyethylene)-block-poly(oxypropylene)-block-poly(oxyethylene) (EOnPOmEOn) type triblock copolymers such as Pluronic P123...
October 18, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Ricardo M F Fernandes, Jing Dai, Oren Regev, Eduardo F Marques, Istvan Furo
When using amphiphilic polymers to exfoliate and disperse carbon nanotubes in water the balance between the hydrophobic and hydrophilic moieties is critical and nontrivial. Here, we investigate the mode of surface attachment of a triblock copolymer, Pluronics F127, composed by a central hydrophobic polypropylene oxide block flanked by hydrophilic polyethylene oxide blocks, onto single-walled carbon nanotubes (SWNT). Crucially, we analyze the composition in dispersant of both the as-obtained dispersion (the supernatant) and the precipitate containing undispersed materials...
October 18, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Aliyeh Ghamkhari, Marjan Ghorbani, Samira Aghbolaghi
Iron oxide nanoparticles (IONs) have been extensively applied in cancer therapy and theranostics due to their admissible magnetic properties, excellent chemical stability and biocompatibility. Herein, a novel stimuli-responsive magnetic nanocomposite was synthesized for cancer therapy; thereby, the triblock copolymer of poly[(2-succinyloxyethylmethacrylate)-b-(N-isopropylacrylamide)-b-dimethylaminoethylmethacrylate) [poly(SEMA-b-NIPAM-b-DMAEMA)] was prepared by reversible addition of fragmentation chain transfer (RAFT) polymerization...
October 11, 2018: Artificial Cells, Nanomedicine, and Biotechnology
Mary Joseph Ngatuni, Hoang M Trinh, Dhananjay Pal, Ashim K Mitra
The objective of this study is to design, develop, and synthesize novel random triblock (RTB) copolymers for sustained delivery of macromolecules. RTB copolymers have not been utilized for the delivery of macromolecules for ocular diseases. RTB copolymers comprising of polyethylene glycol, glycolide, and ɛ-caprolactone blocks were synthesized and assessed for their molecular weights and purity using 1 H-NMR spectroscopy, gel permeation chromatography, FTIR (functionality), and XRD (crystallinity). No toxicity was observed when ocular cell lines were treated with RTB copolymers...
October 10, 2018: AAPS PharmSciTech
Zhongguan Liang, Hao Liu, Jianping Zeng, Jianfei Zhou, Hongjian Li, Hui Xia
Nitrogen-doped microporous carbon spheres (NMCSs) are successfully prepared via carbonization and KOH activation of phenol-formaldehyde resin polymer spheres synthesized by a facile and time-saving one-step hydrothermal strategy using triblock copolymer Pluronic F108 as a soft template under the Stöber-like method condition. The influence of the ethanol/water volume ratios and carbonation temperatures on the morphologies, pore structures and electrochemical performances of the prepared NMCSs are investigated systematically...
October 4, 2018: Nanoscale Research Letters
Kamaljeet Kaur Bawa, Arman Moini Jazani, Chaitra Shetty, Jung Kwon Oh
Polylactide (PLA)-based amphiphilic block copolymers and their nanoassemblies designed with stimuli-responsive degradation (SRD) hold great potential as promising candidates for tumor-targeting drug delivery. However, most of the smart PLA-based nanoassemblies are designed to respond to a single stimulus (typically reduction or acidic pH). Herein, a new strategy is reported to synthesize PLA-based block copolymer micelles exhibiting dual SRD at dual locations (DL-DSRD). The strategy utilizes a combination of ring opening polymerization, controlled radical polymerization, and facile coupling reactions to synthesize an ABA-type PLA-based triblock copolymer with a hydrophilic polymethacrylate (A) and PLA (B) blocks...
October 4, 2018: Macromolecular Rapid Communications
Michael Kuepfert, Aaron Cohen, Olivia Cullen, Marcus Weck
We describe functionalized amphiphilic poly(2-oxazoline)-based triblock copolymers that assemble into shell cross-linked micelles (SCMs). These micelles permit for the site isolation of three incompatible catalysts through compartmentalization, thereby enabling three-step non-orthogonal tandem processes in one pot. In particular, the acid catalyzed ketal hydrolysis to prochiral ketones proceeds in the hydrophilic corona, followed by the Rh-catalyzed asymmetric transfer hydrogenation to enantio-enriched alcohols in the cross-linked shell, and nucleophilic base-catalyzed acylation in the hydrophobic core...
October 1, 2018: Chemistry: a European Journal
Liying Wei, Tugba Demir, Anise M Grant, Vladimir V Tsukruk, Philip J Brown, Igor Luzinov
For decades water and oil repellency of engineering thermoplastics has been achieved with introduction of long-chain perfluoroalkyl substances and moieties (CnF2n+1, n ≥ 7). However, their bioaccumulative and toxicological impact is now widely recognized and, consequently, the substances have been phased out of industrial production and applications. To this end, we have synthesized fluorinated oligomeric triblock polyesters (FOPBs), which do not possess the long-chain perfluoroalkyl segments, and serve as an effective low-surface energy additives to engineering thermoplastics...
October 1, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Michael M Lübtow, Larissa Keßler, Antje Appelt-Menzel, Thomas Lorson, Niklas Gangloff, Marius Kirsch, Selma Dahms, Robert Luxenhofer
A known limitation of polymer micelles for the formulation of hydrophobic drugs is their low loading capacity (LC), which rarely exceeds 20 wt%. One general strategy to overcome this limitation is to increase the amphiphilic contrast, that is, to make the hydrophobic core of the micelles more hydrophobic. However, in the case of poly(2-oxazoline) (POx)-based amphiphilic triblock copolymers, a minimal amphiphilic contrast was reported to be beneficial. Here, this subject is revisited in more detail using long hydrophobic side chains that are either linear (nonyl) or branched (3-ethylheptyl)...
September 5, 2018: Macromolecular Bioscience
James A Dolan, Karolina Korzeb, Raphael Dehmel, Karl C Gödel, Morgan Stefik, Ulrich Wiesner, Timothy D Wilkinson, Jeremy J Baumberg, Bodo D Wilts, Ullrich Steiner, Ilja Gunkel
The efficacy with which solvent vapor annealing (SVA) can control block copolymer self-assembly has so far been demonstrated primarily for the simplest class of copolymer, the linear diblock copolymer. Adding a third distinct block-thereby creating a triblock terpolymer-not only provides convenient access to complex continuous network morphologies, particularly the gyroid phases, but also opens up a route toward the fabrication of novel nanoscale devices such as optical metamaterials. Such applications, however, require the generation of well-ordered 3D continuous networks, which in turn requires a detailed understanding of the SVA process in terpolymer network morphologies...
September 5, 2018: Small
Julia Elistratova, Bulat Akhmadeev, Vladimir Korenev, Maxim Sokolov, Irek Nizameev, Aidar Gubaidullin, Alexandra Voloshina, Asiya Mustafina
The present work introduces Gd3+ complexes with giant keplerate polyanions as a promising basis for MRI contrast agents. The impact of Gd3+ binding with different building blocks of keplerates on the magnetic relaxivity of the complexes is revealed by comparative study of the keplerates [{Mo6O21}12{Mo2O4(OAc)}30]42-, [{Mo6O21}12{Mo2O4(HPO4)}30]72-, and [{Mo6O21}12{Mo2O2S2(OAc)}30]42-. Unprecedentedly high longitudinal and transverse relaxivity values (up to 250 and 300 mM-1 s-1 correspondingly) are achieved for the keplerates possessing edl{Mo2O4(OAc)} and {Mo2O4(HPO42-)} moieties under their 1 : 1 complex formation with Gd3+...
October 3, 2018: Soft Matter
Ryota Tamate, Ryoji Usui, Kei Hashimoto, Yuzo Kitazawa, Hisashi Kokubo, Masayoshi Watanabe
A photo/thermoresponsive ABC triblock copolymer-based ion gel exhibiting photoinduced structural transitions accompanied by significant rheological changes is newly developed. The ABC triblock copolymer comprises an ionic liquid (IL)-phobic A block, an IL-philic B block, and a photo/thermoresponsive C block containing azobenzene moieties. The IL-phobic A block forms a rigid micellar core in an IL over a wide temperature range and the photo/thermoresponsive C block undergoes upper critical solution temperature (UCST)-type phase transition in ILs...
September 17, 2018: Soft Matter
Kritika Goyal, Arpita Konar, B S Hemanth Kumar, Veena Koul
In the present study, engineered lactoferrin (Lf)-conjugated pH and redox-sensitive polymersomes derived from the triblock copolymer polyethylene glycol-S-S-polylactic acid-polycaprolactone (PEG-S-S-PLA-PCL-OH) have been used to deliver bacosides to the brain. Bacosides are classified as triterpenoid saponins and are used in Indian Ayurveda for reversal of amnesia; however, no study has extensively demonstrated their efficacy as a nano-formulation in an animal model. The polymer was synthesized by ring opening polymerization of lactide and ε-caprolactone...
September 27, 2018: Nanoscale
Elena Giuliano, Donatella Paolino, Massimo Fresta, Donato Cosco
Poloxamer 407, also known by the trademark Pluronic® F127, is a water-soluble, non-ionic triblock copolymer that is made up of a hydrophobic residue of polyoxypropylene (POP) between the two hydrophilic units of polyoxyethylene (POE). Poloxamer 407-based hydrogels exhibit an interesting reversible thermal characteristic. That is, they are liquid at room temperature, but they assume a gel form when administered at body temperature, which makes them attractive candidates as pharmaceutical drug carriers. These systems have been widely investigated in the development of mucoadhesive formulations because they do not irritate the mucosal membranes...
September 12, 2018: Pharmaceutics
Elaine Rahmstorf, Volker Abetz
Thermo-reversible supramolecular networks from polyisoprene- block -polystyrene- block -polyisoprene (ISI) triblock copolymers with short, functionalized polyisoprene (PI) blocks were investigated. Functional groups along the PI blocks were hydroxyl groups, ester groups with a carboxylic end-group (-O-CO-CH₂-CH₂-COOH), and urethane groups with an amine end-group-synthesized from various types of diamines-(-O-CO-NH-R-NH₂). Dynamic mechanical analysis (DMA) was performed at temperatures above T g of polystyrene (PS) to investigate the influence of the different functional groups, the molecular weight, and the composition of the triblock copolymers on the materials' properties...
September 12, 2018: Materials
Xianrong Shao, Gizem Bor, Sabah Al-Hosayni, Stefan Salentinig, Anan Yaghmur
The attractiveness of new omega-3 (ω-3) polyunsaturated fatty acid (PUFA) monoglycerides (MAGs) lies in the amphiphilic nature and the beneficial health effects as PUFA precursors in various disorders including cancer, pulmonary hypertension, and inflammatory diseases. For exploring the potential therapeutic applications of these new amphiphilic lipids, particularly as main lipid constituents in the development of nanocarriers for delivery of drugs and PUFAs, it is of paramount importance to gain insight into their self-assembly behavior on exposure to excess water...
October 7, 2018: Physical Chemistry Chemical Physics: PCCP
Duc Nguyen, Vien Huynh, Nguyen Pham, Binh Pham, Algirdas Serelis, Tim Davey, Chris Such, Brian Hawkett
RAFT-mediated free-radical emulsion polymerization is successfully used to synthesize polystyrene nanofibers using triblock amphiphilic macro-RAFT copolymers as stabilizers. The polymerization is under RAFT control, producing various morphologies from spherical particles, nanofibers, nanoplatelets, and polymer vesicles. Optimum conditions are established for the synthesis of predominantly negatively charged polymer nanofibers. Superparamagnetic iron oxide nanoparticles (SPION)-decorated nanofibers are formed by simple mixing of the SPIONs with the fibers at an appropriate pH...
September 10, 2018: Macromolecular Rapid Communications
Naby Hadilou, Ali Navid Khoshgenab, Mitra Amoli-Diva, Rasoul Sadighi-Bonabi
Three magneto-plasmonic nanohybrids were synthesized using Au and Ag-coated Fe3 O4 nanoparticles (NPs) modified dual pH- and temperature-responsive triblock copolymer of poly (butyl methacrylate-co-acrylamide-co-methacrylic acid) to serve as drug carriers with potential of using in both photothermal and controlled/targeted chemo-therapies. The internal superparamagnetic core gives the carriers targeted-delivery characteristics and surface plasmon resonance (SPR)-based noble metallic Au/Ag shells give them on-demand photothermal and photo-triggering release properties...
September 5, 2018: Journal of Pharmaceutical Sciences
Sheng Wang, Guocan Yu, Zhantong Wang, Orit Jacobson, Rui Tian, Li-Sen Lin, Fuwu Zhang, Jing Wang, Xiaoyuan Chen
Nanomedicines have been demonstrated to have passive or active tumor targeting behaviors, which are promising for cancer chemotherapy. However, most nanomedicines still suffer from a suboptimal targeting effect and drug leakage, resulting in unsatisfactory treatment outcome. Herein, a hierarchical responsive nanomedicine (HRNM) is developed for programmed delivery of chemotherapeutics. The HRNMs are prepared via the self-assembly of cyclic Arg-Gly-Asp (RGD) peptide conjugated triblock copolymer, poly(2-(hexamethyleneimino)ethyl methacrylate)-poly(oligo-(ethylene glycol) monomethyl ether methacrylate)-poly[reduction-responsive camptothecin] (PC7A-POEG-PssCPT)...
August 31, 2018: Advanced Materials
Felix Lauterbach, Maarten Rubens, Volker Abetz, Tanja Junkers
Polymers made from isoprene and styrene resemble an important class of synthetic macromolecules found in a wide range of everyday commodity products. Their synthesis is usually limited to radical emulsion or anionic polymerization. Herein, we report on ultrafast photoiniferter reversible addition-fragmentation chain transfer (RAFT) polymerization of isoprene and styrene in a continuous-flow microreactor. The cooperative action of a high photoinitiation efficiency and use of elevated temperatures considerably reduces the reaction times to less than half an hour to give high monomer conversions, allowing for the first time polyisoprene to be yielded from controlled radical polymerization in high definition and reasonable reaction times...
October 22, 2018: Angewandte Chemie
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