Novel approaches to polymer blends based on polymer nanoparticles

Kietzke, Thomas; Neher, Dieter; Landfester, Katharina; Montenegro, Rivelino; Güntner, R.; Scherf, Ullrich

doi:10.1038/nmat889

Cited by 396 publications

(354 citation statements)

References 33 publications

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“…[56][57][58][59][60] Another way to make the blend morphology less sensitive to the film forming conditions was introduced by Kietzke and co-workers. 61 The method involves Figure 4. Short-circuit current density vs. composition of MDMO-PPV:PF1CVTP devices.…”

Section: Factors Influencing the Morphology Of The Photoactive Layer mentioning

confidence: 99%

Nanoscale structure of solar cells based on pure conjugated polymer blends

Veenstra

Loos

Kroon

2007

Progress in Photovoltaics

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This paper gives an overview of the status of photovoltaic devices based on blends of semiconducting polymers. The polymer blends form the bulk heterojunction in these photovoltaic devices. The fundamental mechanisms governing the performance of these devices are discussed as well as the specificities of these all-polymer solar cells. The morphology of the polymer blend layer is expected to influence the device performance of these bulk heterojunctions. An overview is presented of factors that influence the morphology of the active layer of polymer blend photovoltaic devices together with a summary of tools available to study the structure of this layer. An advanced electron microscopy technique is applied to study the morphology of polymer blends of MDMO-PPV and PCNEPV with differing molecular weights. It is shown that the molecular weight of the polymer influences the typical domain size from $200 nm down to less than 5 nm in these bulk heterojunction PV devices. No strong relation is observed between the typical length scale of the phase separated domains and the measured external quantum efficiency, indicating that the phases are intermixed.

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Section: Factors Influencing the Morphology Of The Photoactive Layer mentioning

confidence: 99%

Nanoscale structure of solar cells based on pure conjugated polymer blends

Veenstra

Loos

Kroon

2007

Progress in Photovoltaics

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“…Monodisperse colloidal particles of pure conjugated polymer would be excellent building blocks for these ultimate photonic devices 11,12 . Although semiconducting polymer particles of polypyrrole 13 , polyaniline 14 and polythiophene 15 have been synthesized via oxidation in a dispersion polymerization, colloidal particles of light-emitting conjugated polymers have only been prepared by postpolymerization miniemulsification 16 , reprecipitation 17 or emulsion polymerization using metal-catalysed cross-coupling reactions 18,19 . However, these methods lead to high polydispersities 20 , inhibiting crystallization of the colloids, thus making them unsuitable for creating self-assembled periodic structures, such as photonic crystals.…”

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Monodisperse conjugated polymer particles by Suzuki–Miyaura dispersion polymerization

2012

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The self-assembly of colloidal building blocks into complex and hierarchical structures offers a versatile and powerful toolbox for the creation of new photonic and optoelectronic materials. However, well-defined and monodisperse colloids of semiconducting polymers, which would form excellent building blocks for such self-assembled materials, are not readily available. Here we report the first demonstration of a suzuki-miyaura dispersion polymerization; this method produces highly monodisperse submicrometer particles of a variety of semiconducting polymers. moreover, we show that these monodisperse particles readily self-assemble into photonic crystals that exhibit a pronounced photonic stopgap.

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“…Hence the theory provides a solid framework for tailoring NPs with a priori determined size. Polymeric nanoparticles (NPs) are gaining increasing attention because of their numerous applications in, for instance, physics, chemistry and medicine [1]. The NP size and size distribution are the key parameters often determining their functionality.…”

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confidence: 99%

“…(1) and (3) need to be solved together. In fact, as we are only interested in the final particle size and not its time dependence, we can divide (1) …”

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Controlled Nanoparticle Formation by Diffusion Limited Coalescence

et al. 2012

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Polymeric nanoparticles (NPs) have great application potential in science and technology. Their functionality strongly depends on their size. We present a theory for the size of NPs formed by precipitation of polymers into a bad solvent in the presence of a stabilizing surfactant. The analytical theory is based upon diffusion-limited coalescence kinetics of the polymers. Two relevant time scales, a mixing and a coalescence time, are identified and their ratio is shown to determine the final NP diameter. The size is found to scale in a universal manner and is predominantly sensitive to the mixing time and the polymer concentration if the surfactant concentration is sufficiently high. The model predictions are in good agreement with experimental data. Hence the theory provides a solid framework for tailoring NPs with a priori determined size. Polymeric nanoparticles (NPs) are gaining increasing attention because of their numerous applications in, for instance, physics, chemistry and medicine [1]. The NP size and size distribution are the key parameters often determining their functionality. Therefore, one of the main experimental challenges is to prepare NPs with well controlled dimensions tuned for a particular application. Models of NP formation, allowing one to steer the NP preparation process in the right direction, would simplify the size control significantly.A high level of control over particle size is required in, for example, targeted delivery (e.g., oncology). Size influences the circulating half lifetime and is crucial for selective cellular uptake: NPs between 50 and 200 nm in size are desired in passive cancer tumor targeting as they are too large to harm healthy cells but small enough to penetrate into the diseased ones. In brain imaging, fluorescent dye loaded particles of about 100 nm with biocompatible polymer coatings are used because they produce small, sharply defined injection sites and show no toxicity in vivo or in vitro [2][3][4].Although there are several methods for NP preparation, only few of them permit a high level of control on the particle size and the particle size distribution [2]. Often, a water insoluble moiety (e.g., a drug or a dye), needs to be encapsulated into a carrier polymer and protected by an emulsifying agent, which also makes the NP water soluble. In particular, the so-called nanoprecipitation method permits preparation of nearly monodisperse NPs in a very simple and reproducible way [5]. Typically, an organic phase, which is usually a dilute polymer solution, e.g., polycaprolactone (PCL) in acetone, plus the hydrophobic moiety to be encapsulated, e.g., a drug or a fluorescent dye, is injected by pressure into an aqueous solution of the emulsifying agent, Fig. 1(a). As the organic solvent is chosen to be water-miscible, rapid quenching (towards poor solvent conditions) of the hydrophobic polymer and the drug in water takes place. This results in coalescence of the polymer and the drug into submicron particles decorated by surfactant [2,6]. Alternatively, a block copo...

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Novel approaches to polymer blends based on polymer nanoparticles

Cited by 396 publications

References 33 publications

Nanoscale structure of solar cells based on pure conjugated polymer blends

Nanoscale structure of solar cells based on pure conjugated polymer blends

Monodisperse conjugated polymer particles by Suzuki–Miyaura dispersion polymerization

Controlled Nanoparticle Formation by Diffusion Limited Coalescence

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