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1018 KiB

Open AccessArticle

Hybrid, Nanoscale Phospholipid/Block Copolymer Vesicles

by Seng Koon Lim, Hans-Peter De Hoog, Atul N. Parikh, Madhavan Nallani and Bo Liedberg

Polymers 2013, 5(3), 1102-1114; https://doi.org/10.3390/polym5031102 - 06 Sep 2013

Cited by 60 | Viewed by 12590

Hybrid phospholipid/block copolymer vesicles, in which the polymeric membrane is blended with phospholipids, display interesting self-assembly behavior, incorporating the robustness and chemical versatility of polymersomes with the softness and biocompatibility of liposomes. Such structures can be conveniently characterized by preparing giant unilamellar vesicles [...] Read more.

Hybrid phospholipid/block copolymer vesicles, in which the polymeric membrane is blended with phospholipids, display interesting self-assembly behavior, incorporating the robustness and chemical versatility of polymersomes with the softness and biocompatibility of liposomes. Such structures can be conveniently characterized by preparing giant unilamellar vesicles (GUVs) via electroformation. Here, we are interested in exploring the self-assembly and properties of the analogous nanoscale hybrid vesicles (ca. 100 nm in diameter) of the same composition prepared by film-hydration and extrusion. We show that the self-assembly and content-release behavior of nanoscale polybutadiene-b-poly(ethylene oxide) (PB-PEO)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) hybrid phospholipid/block copolymer vesicles can be tuned by the mixing ratio of the amphiphiles. In brief, these hybrids may provide alternative tools for drug delivery purposes and molecular imaging/sensing applications and clearly open up new avenues for further investigation. Full article

(This article belongs to the Special Issue Supramolecular Chemistry and Self-Assembly 2013)

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755 KiB

Open AccessArticle

DNA-Promoted Auto-Assembly of Gold Nanoparticles: Effect of the DNA Sequence on the Stability of the Assemblies

by Matthieu Doyen, Kristin Bartik and Gilles Bruylants

Polymers 2013, 5(3), 1041-1055; https://doi.org/10.3390/polym5031041 - 22 Jul 2013

Cited by 7 | Viewed by 7139

Abstract

The use of deoxyribonucleic acid (DNA) oligonucleotides has proven to be a powerful and versatile strategy to assemble nanomaterials into two (2D) and three-dimensional (3D) superlattices. With the aim of contributing to the elucidation of the factors that affect the stability of this [...] Read more.

The use of deoxyribonucleic acid (DNA) oligonucleotides has proven to be a powerful and versatile strategy to assemble nanomaterials into two (2D) and three-dimensional (3D) superlattices. With the aim of contributing to the elucidation of the factors that affect the stability of this type of superlattices, the assembly of gold nanoparticles grafted with different DNA oligonucleotides was characterized by UV-Vis absorption spectroscopy as a function of temperature. After establishing an appropriate methodology the effect of (i) the length of the grafted oligonucleotides; (ii) the length of their complementary parts and also of (iii) the simultaneous grafting of different oligonucleotides was investigated. Our results indicate that the electrostatic repulsion between the particles and the cooperativity of the assembly process play crucial roles in the stability of the assemblies while the grafting density of the oligonucleotide strands seems to have little influence. Full article

(This article belongs to the Special Issue Supramolecular Chemistry and Self-Assembly 2013)

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366 KiB

Open AccessArticle

Supramolecular Functionalities Influence the Thermal Properties, Interactions and Conductivity Behavior of Poly(ethylene glycol)/LiAsF₆ Blends

by Jui-Hsu Wang, Chih-Chia Cheng, Oleksii Altukhov, Feng-Chih Chang and Shiao-Wei Kuo

Polymers 2013, 5(3), 937-953; https://doi.org/10.3390/polym5030937 - 04 Jul 2013

Cited by 7 | Viewed by 6801

Abstract

In this study, we tethered terminal uracil groups onto short-chain poly(ethylene glycol) (PEG) to form the polymers, uracil (U)-PEG and U-PEG-U. Through AC impedance measurements, we found that the conductivities of these polymers increased upon increasing the content of the lithium salt, LiAsF [...] Read more.

In this study, we tethered terminal uracil groups onto short-chain poly(ethylene glycol) (PEG) to form the polymers, uracil (U)-PEG and U-PEG-U. Through AC impedance measurements, we found that the conductivities of these polymers increased upon increasing the content of the lithium salt, LiAsF₆, until the Li-to-PEG ratio reached 1:4, with the conductivities of the LiAsF₆/U-PEG blends being greater than those of the LiAsF₆/U-PEG-U blends. The ionic conductivity of the LiAsF₆/U-PEG system reached as high as 7.81 × 10⁻⁴ S/cm at 30 °C. Differential scanning calorimetry, wide-angle X-ray scattering, ⁷Li nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy revealed that the presence of the uracil groups in the solid state electrolytes had a critical role in tuning the glass transition temperatures and facilitating the transfer of Li⁺ ions. Full article

(This article belongs to the Special Issue Supramolecular Chemistry and Self-Assembly 2013)

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969 KiB

Open AccessArticle

Solid-State Organization and Ambipolar Field-Effect Transistors of Benzothiadiazole-Cyclopentadithiophene Copolymer with Long Branched Alkyl Side Chains

by Wojciech Pisula, Hoi Nok Tsao, Dmytro Dudenko, Don M. Cho, Sreenivasa Reddy Puniredd, Yanfei Zhao, Alexey Mavrinskiy, Jie Shu, Michael Ryan Hansen, Martin Baumgarten and Klaus Müllen

Polymers 2013, 5(2), 833-846; https://doi.org/10.3390/polym5020833 - 18 Jun 2013

Cited by 20 | Viewed by 8227

Abstract

The solid-state organization of a benzothiadiazole-cyclopentadithiophene copolymer with long, branched decyl-tetradecyl side chains (CDT-BTZ-C14,10) is investigated. The C14,10 substituents are sterically demanding and increase the π-stacking distance to 0.40 nm from 0.37 nm for the same polymer with linear hexadecyls [...] Read more.

The solid-state organization of a benzothiadiazole-cyclopentadithiophene copolymer with long, branched decyl-tetradecyl side chains (CDT-BTZ-C14,10) is investigated. The C14,10 substituents are sterically demanding and increase the π-stacking distance to 0.40 nm from 0.37 nm for the same polymer with linear hexadecyls (C16). Despite the bulkiness, the C14,10 side chains tend to crystallize, leading to a small chain-to-chain distance between lamellae stacks and to a crystal-like microstructure in the thin film. Interestingly, field-effect transistors based on solution processed layers of CDT-BTZ-C14,10 show ambipolar behavior in contrast to CDT-BTZ-C16 with linear side chains, for which hole transport was previously observed. Due to the increased π-stacking distance, the mobilities are only 6 × 10⁻⁴ cm²/Vs for electrons and 6 × 10⁻⁵ cm²/Vs for holes, while CDT-BTZ-C16 leads to values up to 5.5 cm²/Vs. The ambipolarity is attributed to a lateral shift between stacked backbones provoked by the bulky C14,10 side chains. This reorganization is supposed to change the transfer integrals between the C16 and C14,10 substituted polymers. This work shows that the electronic behavior in devices of one single conjugated polymer (in this case CDT-BTZ) can be controlled by the right choice of the substituents to place the backbones in the desired packing. Full article

(This article belongs to the Special Issue Supramolecular Chemistry and Self-Assembly 2013)

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4333 KiB

Open AccessArticle

One-Dimensional Coordination Polymers of Lanthanide Cations to Cucurbit[7]uril Built Using a Range of Tetrachloride Transition-Metal Dianion Structure Inducers

by Li-Li Liang, Yi Zhao, Kai Chen, Xin Xiao, Jack K. Clegg, Yun-Qian Zhang, Zhu Tao, Sai-Feng Xue, Qian-Jiang Zhu and Gang Wei

Polymers 2013, 5(2), 418-430; https://doi.org/10.3390/polym5020418 - 16 May 2013

Cited by 32 | Viewed by 7244

Abstract

A number of linear coordination polymers have been assembled from lanthanide cations (Ln³⁺) and cucurbit[7]uril (Q[7]) in the presence of [CuCl₄]²⁻or [CoCl₄]²⁻ anions acting as inorganic structure inducers in HCl solution. X-ray diffraction analysis [...] Read more.

A number of linear coordination polymers have been assembled from lanthanide cations (Ln³⁺) and cucurbit[7]uril (Q[7]) in the presence of [CuCl₄]²⁻or [CoCl₄]²⁻ anions acting as inorganic structure inducers in HCl solution. X-ray diffraction analysis has revealed that they form three groups of isomorphous structures. Generally, the complexes of Q[7] with light lanthanide cations (those with atomic number below that of neodymium (Nd³⁺)) are in one group. The other two groups, in which the lanthanide cation has atomic number greater than that of europium (Eu³⁺), seem to follow no obvious rule. For example, the complexes of Q[7] with Eu³⁺ and Gd³⁺cations are in the second group in the presence of [CuCl₄]²⁻ anions, while they are in the third group in the presence of [CoCl₄]²⁻ anions. However, whatever group a given complex belongs to, they all show a common honeycomb-patterned supramolecular assembly, in which [CuCl₄]²⁻or [CoCl₄]²⁻ anions form a honeycomb structure. The Ln³⁺ cations then coordinate to neighboring Q[7] molecules to form 1D coordination polymers that are inserted into the channels of the honeycomb framework, such that each individual coordination polymer is surrounded by [CuCl₄]²⁻or [CoCl₄]²⁻ anions. Full article

(This article belongs to the Special Issue Supramolecular Chemistry and Self-Assembly 2013)

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2267 KiB

Open AccessArticle

Charge-Transfer Complexes Studied by Dynamic Force Spectroscopy

by Alberto Gomez-Casado, Arántzazu Gonzalez-Campo, Yiheng Zhang, Xi Zhang, Pascal Jonkheijm and Jurriaan Huskens

Polymers 2013, 5(1), 269-283; https://doi.org/10.3390/polym5010269 - 06 Mar 2013

Cited by 4 | Viewed by 8686

Abstract

In this paper, the strength and kinetics of two charge-transfer complexes, naphthol-methylviologen and pyrene-methylviologen, are studied using dynamic force spectroscopy. The dissociation rates indicate an enhanced stability of the pyrene-methylviologen complex, which agrees with its higher thermodynamic stability compared to naphthol-methylviologen complex. [...] Read more.

In this paper, the strength and kinetics of two charge-transfer complexes, naphthol-methylviologen and pyrene-methylviologen, are studied using dynamic force spectroscopy. The dissociation rates indicate an enhanced stability of the pyrene-methylviologen complex, which agrees with its higher thermodynamic stability compared to naphthol-methylviologen complex. Full article

(This article belongs to the Special Issue Supramolecular Chemistry and Self-Assembly 2013)

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Review

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2078 KiB

Open AccessReview

Polymer Directed Protein Assemblies

by Patrick Van Rijn

Polymers 2013, 5(2), 576-599; https://doi.org/10.3390/polym5020576 - 22 May 2013

Cited by 32 | Viewed by 12309

Abstract

Protein aggregation and protein self-assembly is an important occurrence in natural systems, and is in some form or other dictated by biopolymers. Very obvious influences of biopolymers on protein assemblies are, e.g., virus particles. Viruses are a multi-protein assembly of which the morphology [...] Read more.

Protein aggregation and protein self-assembly is an important occurrence in natural systems, and is in some form or other dictated by biopolymers. Very obvious influences of biopolymers on protein assemblies are, e.g., virus particles. Viruses are a multi-protein assembly of which the morphology is dictated by poly-nucleotides namely RNA or DNA. This “biopolymer” directs the proteins and imposes limitations on the structure like the length or diameter of the particle. Not only do these bionanoparticles use polymer-directed self-assembly, also processes like amyloid formation are in a way a result of directed protein assembly by partial unfolded/misfolded biopolymers namely, polypeptides. The combination of proteins and synthetic polymers, inspired by the natural processes, are therefore regarded as a highly promising area of research. Directed protein assembly is versatile with respect to the possible interactions which brings together the protein and polymer, e.g., electrostatic, v.d. Waals forces or covalent conjugation, and possible combinations are numerous due to the large amounts of different polymers and proteins available. The protein-polymer interacting behavior and overall morphology is envisioned to aid in clarifying protein-protein interactions and are thought to entail some interesting new functions and properties which will ultimately lead to novel bio-hybrid materials. Full article

(This article belongs to the Special Issue Supramolecular Chemistry and Self-Assembly 2013)

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2704 KiB

Open AccessReview

Structural Diversity of Metallosupramolecular Assemblies Based on the Bent Bridging Ligand 4,4′-Dithiodipyridine

by Rüdiger W. Seidel, Richard Goddard and Iris M. Oppel

Polymers 2013, 5(2), 527-575; https://doi.org/10.3390/polym5020527 - 21 May 2013

Cited by 13 | Viewed by 8312

Abstract

4,4′-Dithiodipyridine (dtdp), also termed 4,4′-dipyridyldisulfide, is a bridging ligand of the 4,4′-bipyridine type. The introduction of the disulfide moiety inevitably leads to a relatively rigid angular structure, which exhibits axial chirality. More than 90 metal complexes containing the dtdp ligand have [...] Read more.

4,4′-Dithiodipyridine (dtdp), also termed 4,4′-dipyridyldisulfide, is a bridging ligand of the 4,4′-bipyridine type. The introduction of the disulfide moiety inevitably leads to a relatively rigid angular structure, which exhibits axial chirality. More than 90 metal complexes containing the dtdp ligand have been crystallographically characterised until now. This review focuses on the preparation and structural diversity of discrete and polymeric metallosupramolecular assemblies constructed from dtdp as bridging ligands. These encompass metallamacrocycles with M₂L₂ topology and coordination polymers with periodicity in one or two dimensions. One-dimensional coordination polymers represent the vast majority of the metallosupramolecular structures obtained from dtdp. These include repeated rhomboids, zigzag, helical and arched chains among other types. In this contribution, we make an attempt to provide a comprehensive account of the structural data that are currently available for metallosupramolecular assemblies based on the bent bridging ligand dtdp. Full article

(This article belongs to the Special Issue Supramolecular Chemistry and Self-Assembly 2013)

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