Funktionale Blockcopolymere: nanostrukturierte Materialien mit neuen Anwendungsmöglichkeiten

Schacher, Felix H.; Rupar, Paul A.; Manners, Ian

doi:10.1002/ange.201200310

Cited by 61 publications

(15 citation statements)

References 384 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This induces a concentration gradient in the surface layers of the cast film. Since block copolymers in selective solvents are well known for their feature to self‐assemble, the concentration gradient further enhances microphase separation by increasing the effective interaction parameter and reducing the relaxation rate of the block copolymer in the more concentrated regions, i.e., closer to the surface 6a. In case of this work, this is reflected by a disorder‐to‐order transition from disordered to weakly segregated spherical micelles, consisting of a PVP core and a PS corona, which then arrange into a cylindrical microphase, where PVP cylinders are embedded in a PS matrix perpendicular to the film surface 2a,3a,8.…”

Section: Introductionmentioning

confidence: 88%

Structure of Nonsolvent‐Quenched Block Copolymer Solutions after Exposure to Electric Fields during Solvent Evaporation

Dreyer

Radjabian

et al. 2019

Adv Materials Inter

View full text Add to dashboard Cite

In this work, an electric field is incorporated during the solvent evaporation step of the block copolymer self‐assembly and nonsolvent induced phase separation (SNIPS) process. This study investigates the structure of nonsolvent‐quenched polystyrene‐block‐poly(2‐vinylpyridine) (PS‐b‐P2VP) and polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) diblock copolymer solutions after exposure to electric fields during solvent evaporation. The results indicate an emphasizing effect of the electric field, enhancing self‐assembly and compensating mediocre experimental parameters to a certain degree. However, the impact is found to be different for the two diblock copolymer membranes depending on the selection of experimental parameters as well as the segregation strength of the systems. In addition, an increasing length of the vertically aligned cylindrical pores by the electric field is observed for both membranes, scaling with the applied voltage. This effect is primarily attributed to the suppression of defects and ill‐alignment of polymer domains in the course of structure formation during SNIPS by the electric field. Scanning electron microscopy is used to image the surface and cross‐sectional morphology of the integral asymmetric membranes.

show abstract

Section: Introductionmentioning

confidence: 88%

Structure of Nonsolvent‐Quenched Block Copolymer Solutions after Exposure to Electric Fields during Solvent Evaporation

Dreyer

Radjabian

et al. 2019

Adv Materials Inter

View full text Add to dashboard Cite

show abstract

“…[1] Cobaltrelated materials, including metallic cobalt, [2] cobalt oxide, [3] cobalt alloy, [4] and cobalt phosphide, [5] have been used in magnetic materials, aerospace engineering, and energy storage. With the development of modern nanoelectronic technology and the increasing demand for nanostructured materials, [6] the preparation of nanostructured inorganic cobaltcontaining materials has become a crucial technological challenge.…”

mentioning

confidence: 99%

Charged Metallopolymers as Universal Precursors for Versatile Cobalt Materials

et al. 2013

View full text Add to dashboard Cite

Inorganic metal-based materials have been widely utilized in catalytic chemistry, life sciences, and engineering. [1] Cobaltrelated materials, including metallic cobalt, [2] cobalt oxide, [3] cobalt alloy, [4] and cobalt phosphide, [5] have been used in magnetic materials, aerospace engineering, and energy storage. With the development of modern nanoelectronic technology and the increasing demand for nanostructured materials, [6] the preparation of nanostructured inorganic cobaltcontaining materials has become a crucial technological challenge. Various methods have been developed to prepare nanoscale inorganic cobalt-containing materials, including electrodeposition, [7] polymeric precursor synthesis, [8] solvothermal/hydrothermal methods, [5b, 9] and sol-gel precipitation. [10] Among them, the utilization of metal-containing polymer precursors to prepare nanostructured cobalt-based materials has been used in particular, for such reasons as controlled molecular weight and architectures offered by well-established controlled/living synthetic methods, various morphologies from polymer self-assembly, [11] and facile manipulation of polymers. [12] As a result, a myriad of metalcontaining polymer precursors in the form of thin films, micelles, or fibers have been designed and utilized for preparation of functional inorganic materials. [8] However, metal-containing polyelectrolytes or charged metallopolymers have been much less studied as precursors to prepare inorganic metal-based materials. [13] Compared with neutral metal-containing polymers, the existence of counterions in charged metallopolymers has several advantages as novel precursors, such as ion-dependent solubility [14] and ioninduced self-assembly. [15] Thus these polyelectrolytes could be universal precursors for access to multifunctional inorganic materials. Unfortunately, it is challenging to perform facile exchange of counterions for charged metallopolymers. Most studies have been limited to specific systems (usually small molecules [16] or super-macromolecules [17] ), thus severely restricting the diversity of charged metallopolymers.Phase transfer has been applied in various organic reactions [18] and utilized in applications such as ionic selfassembly, [19] heterogeneous catalysts, [18,20] and ionic liquids. [21] However, the utilization of phase transfer to tune metalassociated counterions for charged metallopolymers is much less explored. [15, 19b] We have recently demonstrated ion exchange between hexafluorophosphate (PF 6 À ) and tetraphenyl borate (BPh 4 À ) ions in cationic cobaltocenium-containing monomers/polymers, which was clearly a phase transfer-driven reaction. [14b, 22] But this specific reaction was only limited for BPh 4 À anions. It is still challenging to apply a powerful technique to access other types of counterions for cobaltocenium-containing polymers.Herein, we report a facile phase-transfer ion-exchange method to prepare cationic cobaltocenium-containing polyelectrolytes with diverse counterions by the use of tetrabutylam...

show abstract

“…Especially for block copolymers, the range of possible applications is continuously expanding and spans over different scientific disciplines like biology, medicine, chemistry, materials science, and physics. 16,17 Poly(2-oxazoline)s represent an interesting polymer class accessible via cationic ring-opening polymerization (CROP). They can be regarded as pseudo-peptides and, for poly(2-ethyl-2-oxazoline) (PEtOx), it has been demonstrated that the resulting water-soluble materials are biocompatible and possess similar properties as polyethylene glycol.…”

Section: Introductionmentioning

confidence: 99%

A strong cationic Brønsted acid, [H(OEt₂)₂][Al{OC(CF₃)₃}₄], as an efficient initiator for the cationic ring-opening polymerization of 2-alkyl-2-oxazolines

Rudolph¹,

Kempe²,

Crotty³

et al. 2013

Polym. Chem.

Self Cite

View full text Add to dashboard Cite

In this contribution, the cationic ring-opening polymerization (CROP) and copolymerization of 2-ethyl-2-oxazoline and 2-tert-butyl-2-oxazoline using a strong cationic Brønsted acid, [H(OEt 2 ) 2 ][Al {OC(CF 3 ) 3 } 4 ], as an initiator are described. First, various poly(2-ethyl-2-oxazoline) (PEtOx) samples are prepared and the living/controlled character of the reaction is demonstrated. We could show that the microwave-assisted CROP of EtOx using this initiator system proceeds faster if compared to classical initiators such as methyl tosylate. These results were then extended to the CROP of poly(2-tertbutyl-2-oxazoline) (PtButOx) and to PEtOx/PtButOx random and block copolymers of different compositions. The resulting materials were characterized using spectroscopic ( 1 H-NMR, FT-IR), chromatographic (SEC), and thermoanalytic techniques (DSC, TGA). Although samples containing more than 13 wt% PtButOx were insoluble in common organic solvents, thermogravimetric (TGA, DSC), spectroscopic (IR), scattering methods (wide-angle X-ray scattering, WAXS), and SEC in hexafluoro-iso-propanol (HFIP) hinted at the successful formation of block copolymers. In particular, WAXS revealed increasing crystallinity for samples containing higher weight fractions of PtButOx.

show abstract

Funktionale Blockcopolymere: nanostrukturierte Materialien mit neuen Anwendungsmöglichkeiten

Cited by 61 publications

References 384 publications

Structure of Nonsolvent‐Quenched Block Copolymer Solutions after Exposure to Electric Fields during Solvent Evaporation

Structure of Nonsolvent‐Quenched Block Copolymer Solutions after Exposure to Electric Fields during Solvent Evaporation

Charged Metallopolymers as Universal Precursors for Versatile Cobalt Materials

A strong cationic Brønsted acid, [H(OEt₂)₂][Al{OC(CF₃)₃}₄], as an efficient initiator for the cationic ring-opening polymerization of 2-alkyl-2-oxazolines

Contact Info

Product

Resources

About

Funktionale Blockcopolymere: nanostrukturierte Materialien mit neuen Anwendungsmöglichkeiten

Cited by 61 publications

References 384 publications

Structure of Nonsolvent‐Quenched Block Copolymer Solutions after Exposure to Electric Fields during Solvent Evaporation

Structure of Nonsolvent‐Quenched Block Copolymer Solutions after Exposure to Electric Fields during Solvent Evaporation

Charged Metallopolymers as Universal Precursors for Versatile Cobalt Materials

A strong cationic Brønsted acid, [H(OEt2)2][Al{OC(CF3)3}4], as an efficient initiator for the cationic ring-opening polymerization of 2-alkyl-2-oxazolines

Contact Info

Product

Resources

About

A strong cationic Brønsted acid, [H(OEt₂)₂][Al{OC(CF₃)₃}₄], as an efficient initiator for the cationic ring-opening polymerization of 2-alkyl-2-oxazolines