The Synthesis and Characterization of Energy-Conducting Polymers with Pendant Inorganic Chromophores

2004 ◽  
Vol 847 ◽  
Author(s):  
James H. Alstrum-Acevedo ◽  
Joseph M. DeSimone ◽  
C. K. Schauer ◽  
John M. Papanikolas
Keyword(s):  
Solid State ◽  
Transition Metal ◽  
Self Assembly ◽  
Visible Spectrum ◽  
Nanoscale Structures ◽  
Macromolecular Assemblies ◽  
Polymeric Scaffold ◽  
Transmission Electron ◽  
Reversible Addition ◽  
And Performance

ABSTRACTWe are interested in the synthesis, characterization, and performance evaluation of functional nanoscale materials comprised of a polymeric scaffold with appended cationic transition-metal lumiphores. We have developed a methodology to prepare, spectroscopically characterize, and evaluate a series of organic copolymers functionalized with inorganic chromophores. Preparation of these hybrid systems first involves the synthesis of a linear AB diblock copolymeric scaffold in which A is polystyrene (PS) and B is poly(p-tert-butoxycarbonyloxystyrene) (PStBOC), using Reversible Addition-Fragmentation chain-Transfer (RAFT) radical polymerization. The PStBOC block (B) was converted into poly(4-hydroxystyrene) by acid hydrolysis of the t-BOC moieties, and Ru(II) trisbipyridyl complexes were covalently appended using standard ester coupling reagents. These lumiphores were selected due to their strong absorbance in the visible spectrum, chemical/photochemical stability, useful redox properties, and long-lived excited state lifetimes. Attachment of the cationic transition-metal chromophores to block B of these linear AB diblock copolymeric arrays is expected to promote solid-state self-assembly into nanoscale structures. The metal-loaded macromolecular assemblies were characterized spectroscopically and the determination of the solid-state morphology of films of these materials was investigated using Transmission Electron Microscopy (TEM).

Synthesis of Polystyrene-B-Poly(Ethylene Oxide)monomethyl Ethermethacrylate Block Copolymers and its Self-Assembly in Aqueous Solution

2011 ◽  
Vol 284-286 ◽  
pp. 769-772
Author(s):  
Qian Qian You ◽  
Pu Yu Zhang
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Block Copolymers ◽  
Self Assembly ◽  
Chain Transfer ◽  
Functional Group ◽  
Transmission Electron ◽  
Reversible Addition ◽  
Ft Ir ◽  
A Chain

The block copolymer of PSt-b-POEOMA with the end of -COOH functional group has been synthesized by reversible addition fragmentation chain-transfer (RAFT) using S,S′-Bis(α,α′-dimethyl-α′′-acetic acid)-trithiocarbonate (BDATC) as a chain transfer agent. The architectures of the copolymers were confirmed by FT-IR and 1HNMR spectra. GPC analysis was used to estimate the molecular weight and the molecular weight distribution of the copolymers. Meanwhile, The nanostructures of the block copolymers PSt-b-POEOMA micelles formed in aqueous solution were observed by transmission electron microscopy (TEM) and dynamic light scattering (DLS).

Radio-opaque Micelles for X-ray Imaging

2014 ◽  
Vol 67 (1) ◽  
pp. 78 ◽  
Author(s):  
Zhiyong Wang ◽  
Teddy Chang ◽  
Luke Hunter ◽  
Andrew M. Gregory ◽  
Marcel Tanudji ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Self Assembly ◽  
Block Size ◽  
Drug Carriers ◽  
Block Copolymerization ◽  
X Ray ◽  
Transmission Electron ◽  
X Ray Imaging ◽  
Reversible Addition ◽  
Rate Of Polymerization

Block copolymers based on iodinated monomers were prepared with the aim of creating nanoparticles as contrast agents suitable for X-ray imaging. Reversible addition–fragmentation chain-transfer polymerization was employed to synthesize block copolymers based on oligo(ethylene glycol) methylether methacrylate (OEGMEMA) and 2-[2′,3′,5′-triiodobenzoyl]oxyethyl methacrylate (METB). The polymerization of METB was found to be slow owing to the low solubility of the monomer, which does not allow high enough concentration to achieve a fast rate of polymerization. However, the block copolymerization was well controlled, resulting in several block copolymers, POEGMEMA-b-PMETB, which were further investigated in regards to their self-assembly in water. Micelles were prepared using POEGMEMA55-b-PMETB18, POEGMEMA55-b-PMETB32, POEGMEMA100-b-PMETB22, and POEGMEMA100-b-PMETB32. Transmission electron microscopy and dynamic light scattering revealed micelle sizes between 30 and 45 nm depending on the block size. The micelles were found to show a strong contrast similar to BaSO4 and Visipaque (iodixanol) during X-ray analysis. These micelles can now further be employed as drug carriers or can be conjugated to a bioactive group for targeting.

scholarly journals Synthesis of Terpyridine-Terminated Amphiphilic Block Copolymers and Their Self-Assembly into Metallo-Polymer Nanovesicles

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 601 ◽  
Author(s):  
Tatyana Elkin ◽  
Stacy Copp ◽  
Ryan Hamblin ◽  
Jennifer Martinez ◽  
Gabriel Montaño ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Block Copolymers ◽  
Self Assembly ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Amphiphilic Block Copolymers ◽  
Transmission Electron ◽  
Reversible Addition ◽  
Efficient Route ◽  
High Yields

Polystyrene-b-polyethylene glycol (PS-b-PEG) amphiphilic block copolymers featuring a terminal tridentate N,N,N-ligand (terpyridine) were synthesized for the first time through an efficient route. In this approach, telechelic chain-end modified polystyrenes were produced via reversible addition-fragmentation chain-transfer (RAFT) polymerization by using terpyridine trithiocarbonate as the chain-transfer agent, after which the hydrophilic polyethylene glycol (PEG) block was incorporated into the hydrophobic polystyrene (PS) block in high yields via a thiol-ene process. Following metal-coordination with Mn2+, Fe2+, Ni2+, and Zn2+, the resulting metallo-polymers were self-assembled into spherical, vesicular nanostructures, as characterized by dynamic light scattering and transmission electron microscopy (TEM) imaging.

RAFT Chemistry and Huisgen 1,3-Dipolar Cycloaddition: A Route to Block Copolymers of Vinyl Acetate and 6-O-Methacryloyl Mannose?

2007 ◽  
Vol 60 (6) ◽  
pp. 405 ◽  
Author(s):  
S. R. Simon Ting ◽  
Anthony M. Granville ◽  
Damien Quémener ◽  
Thomas P. Davis ◽  
Martina H. Stenzel ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Vinyl Acetate ◽  
Self Assembly ◽  
Average Molecular Weight ◽  
Dipolar Cycloaddition ◽  
Hydrodynamic Diameter ◽  
Transmission Electron ◽  
Reversible Addition ◽  
Polymer Distribution ◽  
Two Phases

The present communication explores a novel avenue to glycopolymer-block-poly(vinyl acetate) polymers by a combination of reversible addition fragmentation chain transfer (RAFT) chemistry and Huisgen 1,3-dipolar cycloaddition (i.e., so-called ‘click’ chemistry) under mild reaction conditions. Such block copolymers are—because of the strongly disparate reactivity of the two monomers—otherwise not obtainable. Poly(vinyl acetate) that has an azide end group (Mn 6800 g mol–1, PDI 1.15) was treated with poly(6-O-methacryloyl mannose) (Mn 7600 g mol–1, PDI 1.11) in the presence of 1,8-diaza[5,4,0]bicycloundec-7-ene and copper(i) iodide. The resulting poly(vinyl acetate)-block-poly(6-O-methacryloyl mannose) had a number-average molecular weight of 15400 g mol–1 and a PDI of 1.48, which indicates that while the cycloaddition had occurred the resulting polymer distribution featured a considerable width. The resulting slightly amphiphilic block copolymer was subsequently investigated with regard to its self-assembly in aqueous solution. Dynamic light scattering studies indicated a hydrodynamic diameter of close to 200 nm. Transmission electron microscopy studies indicate the formation of rods as well as spheres with transitions between these two phases. However, the segregation between core and shell in the spheres is not pronounced; such behaviour is expected for weakly amphiphilic block copolymers.

Self-assembly using stannylplatinum(IV) halide complexes as ligands for organotin halides

2002 ◽  
Vol 80 (11) ◽  
pp. 1451-1457 ◽  
Author(s):  
Michael C Janzen ◽  
Michael C Jennings ◽  
Richard J Puddephatt
Keyword(s):  
Coordination Chemistry ◽  
Solid State ◽  
Transition Metal ◽  
Self Assembly ◽  
Metal Halides ◽  
Polymeric Structure ◽  
Distorted Octahedral ◽  
Structure Determinations ◽  
Halide Complexes ◽  
Self Association

The possibility of forming extended structures by self-association using transition metal halides as donors to organotin acceptors has been investigated. The stannylplatinum(IV) complex [PtClMe2(SnMe2Cl)(bu2bpy)] forms a 1:1 adduct [PtClMe2(SnMe2Cl)(bu2bpy)]·Me2SnCl2 with Me2SnCl2 in which the organoplatinum complex acts as a donor to the organotin halide. Similarly, [PtClMe2(SnMeCl2)(bu2bpy)] forms adducts [PtClMe2(SnMeCl2)(bu2bpy)]·MeSnCl3 or [PtClMe2(SnMeCl2)(bu2bpy)]·Me2SnCl2, and [{PtClMe2(bu2bpy)}2(µ-SnCl2)] forms [{PtClMe2(bu2bpy)}2(µ-SnCl2)]·Me2SnCl2. Structure determinations on selected compounds show that the donor is the Pt-Cl group and the acceptor tin centre is 5-coordinate. In the similar bromo complex [PtBrMe2(SnMeBr2)(bu2bpy)]·Me2SnBr2 both the Pt-Br and PtSn-Br groups coordinate to the Me2SnBr2 acceptor with short (3.14 or 3.29 Å) and long (3.99 or 4.05 Å) contacts, respectively, so that the acceptor tin centre adopts distorted octahedral stereochemistry in the solid state and a folded polymeric structure is formed. Reaction of [{PtClMe2(bu2bpy)}2(µ-SnCl2)] with AgO3SCF3 yields the complex [{PtClMe2(bu2bpy)}(µ-SnCl2){PtMe2(bu2bpy)O3SCF3}], which is fluxional in solution.Key words: platinum, tin, self-assembly, coordination chemistry, organometallics.

Controlled RAFT synthesis of polystyrene-b-poly(acrylic acid)-b-polystyrene block copolymers and their self-assembly in an ionic liquid [BMIM][PF6]

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Linping Zheng ◽  
Yun Chai ◽  
Yang Liu ◽  
Puyu Zhang
Keyword(s):  
Ionic Liquid ◽  
Block Copolymers ◽  
Self Assembly ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Amphiphilic Block Copolymers ◽  
Transmission Electron ◽  
Reversible Addition ◽  
Potential Applications ◽  
Increasing Temperature

AbstractThe block copolymer of polystyrene-block-polyacrylate-blockpolystyrene (PSt-PAA-PSt) has been synthesized by reversible addition fragmentation chain-transfer (RAFT) polymerization using S,S′-Bis(α,α′-dimethyl-α′′-acetic acid)-trithiocarbonate (BDATC) as chain transfer agent. Three copolymers form micelles in an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]). The nanostructures of the PSt-PAA-PSt micelles formed in ionic liquid were observed by transmission electron microscopy (TEM). The self-assembled morphologies of the micelles are strongly dependent on the length of PAA block chains when the chain length of PS is fixed. The affinity of PAA chains for water and [BMIM][PF6] reverses with increasing temperature. Research results show that the copolymer with low polydispersity can be obtained by controlling polymerization, and the flexibility of amphiphilic block copolymers for controlling nanostructure in an ionic liquid presents potential applications in many arenas.

scholarly journals Semi-Fluorinated Di and Triblock Copolymer Nano-Objects Prepared via RAFT Alcoholic Dispersion Polymerization (PISA)

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2502
Author(s):  
Gregoire Desnos ◽  
Adrien Rubio ◽  
Chaimaa Gomri ◽  
Mathias Gravelle ◽  
Vincent Ladmiral ◽  
...  
Keyword(s):  
Self Assembly ◽  
Triblock Copolymer ◽  
Dispersion Polymerization ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
The Self ◽  
The Core ◽  
Transmission Electron ◽  
Reversible Addition ◽  
Polymerization Conditions

A set of well-defined amphiphilic, semi-fluorinated di and triblock copolymers were synthesized via polymerization-induced self-assembly (PISA) under alcoholic dispersion polymerization conditions. This study investigates the influence of the length, nature and position of the solvophobic semi-fluorinated block. A poly(N,N-dimethylaminoethyl methacrylate) was used as the stabilizing block to prepare the di and tri block copolymer nano-objects via reversible addition-fragmentation chain transfer (RAFT) controlled dispersion polymerization at 70 °C in ethanol. Benzylmethacrylate (BzMA) and semi-fluorinated methacrylates and acrylates with 7 (heptafluorobutyl methacrylate (HFBMA)), 13 (heneicosafluorododecyl methacrylate (HCFDDMA)) and 21 (tridecafluorooctyl acrylate (TDFOA)) fluorine atoms were used as monomers for the core-forming blocks. The RAFT polymerization of these semi-fluorinated monomers was monitored by SEC and 1H NMR. The evolution of the self-assembled morphologies was investigated by transmission electron microscopy (TEM). The results demonstrate that the order of the blocks and the number of fluorine atoms influence the microphase segregation of the core-forming blocks and the final morphology of the nano-objects.

Current Status of Solid-State X-Ray Systems

1985 ◽  
Vol 43 ◽  
pp. 158-161
Author(s):  
Martin Peckerar ◽  
Anastasios Tousimis
Keyword(s):  
Solid State ◽  
Electric Fields ◽  
Spectral Lines ◽  
Current Status ◽  
Mobile Charge ◽  
Electron Hole ◽  
X Ray ◽  
Sensing Systems ◽  
Transmission Electron ◽  
Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

Transmission Electron Microscopy of an Aluminum-Silver-Stainless Steel Solid State Bond

1985 ◽  
Vol 43 ◽  
pp. 172-173
Author(s):  
M. J. Carr ◽  
J. F. Shewbridge ◽  
T. O. Wilford
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid State ◽  
Specimen Preparation ◽  
Dimensional Control ◽  
Tem Analysis ◽  
Metal Parts ◽  
Dissimilar Metal ◽  
Transmission Electron ◽  
Short Time

Strong solid state bonds are routinely produced between physical vapor deposited (PVD) silver coatings deposited on sputter cleaned surfaces of two dissimilar metal parts. The low temperature (200°C) and short time (10 min) used in the bonding cycle are advantageous from the standpoint of productivity and dimensional control. These conditions unfortunately produce no microstructural changes at or near the interface that are detectable by optical, SEM, or microprobe examination. Microstructural problems arising at these interfaces could therefore easily go undetected by these techniques. TEM analysis has not been previously applied to this problem because of the difficulty in specimen preparation. The purpose of this paper is to describe our technique for preparing specimens from solid state bonds and to present our initial observations of the microstructural details of such bonds.

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