Controlling the pore size in conjugated polymer films via crystallization-driven phase separation

Soft Matter ◽  
2019 ◽  
Vol 15 (14) ◽  
pp. 2981-2989 ◽  
Author(s):  
Shaowen Guo ◽  
Yaguang Lu ◽  
Binghua Wang ◽  
Changyu Shen ◽  
Jingbo Chen ◽  
...  
Keyword(s):  
Phase Separation ◽  
Pore Size ◽  
Polymer Films ◽  
Conjugated Polymer ◽  
Pore Sizes ◽  
Wide Range ◽  
Crystallizable Polymer

In this study, conductive porous P3HT membranes with a wide range of pore sizes were prepared by crystallization-driven phase separation based on blending P3HT with a crystallizable polymer.

Porosity and pore size distribution of shales: a case study of the Carynginia Formation, Perth Basin, Western Australia

2017 ◽  
Vol 57 (2) ◽  
pp. 660
Author(s):  
M. Nadia Testamanti ◽  
Reza Rezaee ◽  
Jie Zou
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Gas Adsorption ◽  
Pore Network ◽  
Pore Sizes ◽  
Wide Range ◽  
Pore Characterisation ◽  
Shale Reservoirs ◽  
Mercury Injection Capillary Pressure

The evaluation of the gas storage potential of shale reservoirs requires a good understanding of their pore network. Each of the laboratory techniques used for pore characterisation can be applied to a specific range of pore sizes; but if the lithology of the rock is known, usually one suitable method can be selected to investigate its pore system. Shales do not fall under any particular lithological classification and can have a wide range of minerals present, so a combination of at least two methods is typically recommended for a better understanding of their pore network. In the laboratory, the Low-Pressure Nitrogen Gas Adsorption (LP-N2-GA) technique is typically used to examine micropores and mesopores, and Mercury Injection Capillary Pressure (MICP) tests can identify pore throats larger than 3 nm. In contrast, a wider range of pore sizes in rock can be screened with Nuclear Magnetic Resonance (NMR), either in laboratory measurements made on cores or through well logging, provided that the pores are saturated with a fluid. The pore network of a set of shale core samples from the Carynginia Formation was investigated using a combination of laboratory methods. The cores were studied using the NMR, LP-N2-GA and MICP techniques, and the experimental porosity and pore size distribution results are presented. When NMR results were calibrated with MICP or LP-N2-GA measurements, then the pore size distribution of the shale samples studied could be estimated.

scholarly journals Templated Growth of Fullerene C60 Crystals by Triptycene in  Polymer Blend Films

2021 ◽  
Author(s):  
◽  
Cole Ross Lomas
Keyword(s):  
Solar Cells ◽  
Phase Separation ◽  
Solar Cell ◽  
Polymer Film ◽  
Active Layer ◽  
Polymer Films ◽  
Conjugated Polymer ◽  
Electronic Devices ◽  
Fullerene C60 ◽  
Film Morphology

<p>Molecular semiconductors such as fullerene C60 have become ubiquitous components of organic electronic devices, owing to their electronic structure and favourable material processing properties. In most conjugated polymer-fullerene films that form the active layer in bulk heterojunction (BHJ) organic solar cells, organisation of the fullerene phases to the correct nanoscale dimensions for exciton charge separation and transportation to the device electrodes is driven by excess fullerene addition. While this approach can deliver acceptable film morphology for a BHJ solar cell, it is not optimal as the photoactive polymer component of the film becomes diluted by C60 thereby reducing device efficiency. This motivates a supramolecular approach as an alternative method to control fullerene assembly and give morphological control of conjugated polymer films. Triptycene (TPC) is a readily available molecule whose rigid paddle wheel structure and hydrophobicity present three excellent C60 binding cavities. Triptycene has the potential to template the macroscopic assembly of fullerene molecules within a polymer-fullerene blend film, thereby controlling phase separation without excess fullerene addition. In this project, the ability of TPC to template the assembly of C60 was investigated in single crystals, polymer films, and in functional electronic devices. Blue-shifted fluorescence from TPC·C60 co-crystals was used as a spectroscopic signature to probe the molecular environment of C60 dispersed through an optically transparent polystyrene polymer film, and confirm that TPC hosts C60 molecules within the polymer matrix. Ultraviolet-visible (UV-Vis) spectroscopy of the polystyrene:C60:TPC films confirmed a reduction in the orbital overlap between adjacent C60 molecules providing further evidence that TPC had spatially separated C60 molecules upon templating the macroscopic assembly. When TPC was added to conjugated polymer poly[2-methoxy-5-(2-ethyhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and MEHPPV: C60 films as a blend additive, fluorescence spectroscopy identified two unique effects: (1) the suppression of excimer states when TPC spatially separated the conjugated polymer chains, and (2) the assembly of C60 into larger domains to drive polymer and C60 phase separation, giving morphological control of the polymer film. The fabrication of polystyrene:C60:TPC sandwich devices showed the electronic conduction of C60 was unaltered by spatial separation and reduction in electronic coupling between neighbouring C60 molecules caused by TPC templation. MEHPPV: C60 BHJ solar cells suffered a loss in photocurent when TPC was added to the active layer when compared to fabricated devices that used excess fullerene addition to control film morphology. However, due to time constraints, only one polymer film composition was able to be tested. Since the polymer film morphology was shown to be sensitive to the molar ratios of C60 and TPC, there is immense potential to further investigate TPC as a blend additive in conjugated polymer films and optimise the film composition to obtain desirable morphology for a BHJ solar cell. The functionalisation of TPC could provide a method to further enhance interactions between TPC and C60 and provide greater control over C60 self-assembly within a polymer film.</p>

scholarly journals Templated Growth of Fullerene C60 Crystals by Triptycene in  Polymer Blend Films

2021 ◽  
Author(s):  
◽  
Cole Ross Lomas
Keyword(s):  
Solar Cells ◽  
Phase Separation ◽  
Solar Cell ◽  
Polymer Film ◽  
Active Layer ◽  
Polymer Films ◽  
Conjugated Polymer ◽  
Electronic Devices ◽  
Fullerene C60 ◽  
Film Morphology

<p>Molecular semiconductors such as fullerene C60 have become ubiquitous components of organic electronic devices, owing to their electronic structure and favourable material processing properties. In most conjugated polymer-fullerene films that form the active layer in bulk heterojunction (BHJ) organic solar cells, organisation of the fullerene phases to the correct nanoscale dimensions for exciton charge separation and transportation to the device electrodes is driven by excess fullerene addition. While this approach can deliver acceptable film morphology for a BHJ solar cell, it is not optimal as the photoactive polymer component of the film becomes diluted by C60 thereby reducing device efficiency. This motivates a supramolecular approach as an alternative method to control fullerene assembly and give morphological control of conjugated polymer films. Triptycene (TPC) is a readily available molecule whose rigid paddle wheel structure and hydrophobicity present three excellent C60 binding cavities. Triptycene has the potential to template the macroscopic assembly of fullerene molecules within a polymer-fullerene blend film, thereby controlling phase separation without excess fullerene addition. In this project, the ability of TPC to template the assembly of C60 was investigated in single crystals, polymer films, and in functional electronic devices. Blue-shifted fluorescence from TPC·C60 co-crystals was used as a spectroscopic signature to probe the molecular environment of C60 dispersed through an optically transparent polystyrene polymer film, and confirm that TPC hosts C60 molecules within the polymer matrix. Ultraviolet-visible (UV-Vis) spectroscopy of the polystyrene:C60:TPC films confirmed a reduction in the orbital overlap between adjacent C60 molecules providing further evidence that TPC had spatially separated C60 molecules upon templating the macroscopic assembly. When TPC was added to conjugated polymer poly[2-methoxy-5-(2-ethyhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and MEHPPV: C60 films as a blend additive, fluorescence spectroscopy identified two unique effects: (1) the suppression of excimer states when TPC spatially separated the conjugated polymer chains, and (2) the assembly of C60 into larger domains to drive polymer and C60 phase separation, giving morphological control of the polymer film. The fabrication of polystyrene:C60:TPC sandwich devices showed the electronic conduction of C60 was unaltered by spatial separation and reduction in electronic coupling between neighbouring C60 molecules caused by TPC templation. MEHPPV: C60 BHJ solar cells suffered a loss in photocurent when TPC was added to the active layer when compared to fabricated devices that used excess fullerene addition to control film morphology. However, due to time constraints, only one polymer film composition was able to be tested. Since the polymer film morphology was shown to be sensitive to the molar ratios of C60 and TPC, there is immense potential to further investigate TPC as a blend additive in conjugated polymer films and optimise the film composition to obtain desirable morphology for a BHJ solar cell. The functionalisation of TPC could provide a method to further enhance interactions between TPC and C60 and provide greater control over C60 self-assembly within a polymer film.</p>

scholarly journals The use of gel chromatography for the determination of sizes and relative molecular masses of proteins. Interpretation of calibration curves in terms of gel-pore-size distribution

1987 ◽  
Vol 243 (2) ◽  
pp. 399-404 ◽  
Author(s):  
M le Maire ◽  
A Ghazi ◽  
J V Møller ◽  
L P Aggerbeck
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Linear Relationship ◽  
Size Distribution ◽  
Gel Chromatography ◽  
Linear Calibration ◽  
Pore Sizes ◽  
Calibration Curves ◽  
Wide Range

The separation of proteins by gel-exclusion chromatography has been explained in terms of partitioning of the macromolecules within the gel by a distribution of pores of various radii. The assumption that the distribution of pore sizes is Gaussian has led to the prediction of a linear relationship between the molecular Stokes radius (RS) of the protein and the function erf-1 (1-KD), where KD is the partition coefficient [Ackers (1967) J. Biol. Chem. 242, 3237-3238]. Since careful calibrations of classical (agarose and dextran) gels and h.p.l.c. gels have shown that such a linear relationship is not verified experimentally over a wide range of native protein sizes, we have reinvestigated the model of Ackers (above reference). We show that Ackers' (above reference) derivation is not valid except for a particular Gaussian distribution of pore sizes centred at the origin. Relaxation of this restriction to allow for other types of Gaussian distributions cannot account for the non-linear calibration curves that we have obtained. Instead we show that the pore-size distribution can be calculated from the experimentally determined function KD = f(RS) and that this distribution is bimodal (non-Gaussian). One distribution is centred below 2 nm, whereas the mean value of the second one is around 6-8 nm. The minimum in this bimodal distribution corresponds, for some gels, to a region of poor resolution, which needs to be appreciated for the proper use of gel chromatography in the determination of molecular size.

Laser light scattering as a probe of phase separation in conjugated polymer films of donor-acceptor blends

2006 ◽  
Author(s):  
S. G. Elizarov ◽  
A. E. Ozimova ◽  
A. N. Khodarev ◽  
D. Yu. Paraschuk ◽  
S. A. Arnautov ◽  
...  
Keyword(s):  
Phase Separation ◽  
Light Scattering ◽  
Polymer Films ◽  
Conjugated Polymer ◽  
Laser Light ◽  
Laser Light Scattering ◽  
Donor Acceptor

Tailoring Structure and Field-Effect Characteristics of Ultrathin Conjugated Polymer Films via Phase Separation

2018 ◽  
Vol 10 (11) ◽  
pp. 9602-9611 ◽  
Author(s):  
Feng Ge ◽  
Shiyu Wei ◽  
Zhen Liu ◽  
Guiheng Wang ◽  
Xiaohong Wang ◽  
...  
Keyword(s):  
Phase Separation ◽  
Polymer Films ◽  
Conjugated Polymer ◽  
Field Effect

Manufacturing of Porous Polydimethylsiloxane (PDMS) Plates Using Solvent Evaporation Induced Phase Separation Technique

2020 ◽  
Author(s):  
Mohammad Abshirini ◽  
M. Cengiz Altan ◽  
Yingtao Liu ◽  
Mrinal C. Saha ◽  
Laura Cummings ◽  
...  
Keyword(s):  
Phase Separation ◽  
Porous Structure ◽  
Pore Size ◽  
Average Pore Size ◽  
Solvent Evaporation ◽  
Separation Technique ◽  
Solvent Ratio ◽  
Average Pore ◽  
Wide Range ◽  
Curing Cycle

Abstract This paper presents the fabrication and characterization of porous polydimethylsiloxane (PDMS) plates. The framework for obtaining porous PDMS is based on the solvent evaporation induced phase separation technique. A mixture of PDMS, water, and tetrahydrofuran (THF) with different concentrations is prepared. The three phases are stirred to reach a highly stable and viscous solution. The THF and water phases are evaporated during a curing cycle by applying a stepping heat treatment. The porous PDMS sheets with a wide range of pore sizes are fabricated by controlling the ratio of water to THF in the mixture. The confocal microscopy images are used to characterize the average pore size and the pore size distribution in the structures. Dogbone samples following the ASTM standard D412 are cut from the porous plates by utilizing a designed cutting die and mechanical press. The specimens are tested under tensile loading to evaluate the effect of the pore size on the mechanical properties of the porous structure. The results demonstrate the ability of the proposed solvent evaporation method to control the stiffness of the porous structure by changing the non-solvent to the solvent ratio in the mixture.

Scanning-tunneling spectroscopy on conjugated polymer films

2003 ◽  
Vol 771 ◽  
Author(s):  
M. Kemerink ◽  
S.F. Alvarado ◽  
P.M. Koenraad ◽  
R.A.J. Janssen ◽  
H.W.M. Salemink ◽  
...  
Keyword(s):  
Polymer Films ◽  
Conjugated Polymer ◽  
Three Dimensional ◽  
Field Enhancement ◽  
Direct Consequence ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Band Alignment ◽  
Scanning Tunneling ◽  
Order Of Magnitude

AbstractScanning-tunneling spectroscopy experiments have been performed on conjugated polymer films and have been compared to a three-dimensional numerical model for charge injection and transport. It is found that field enhancement near the tip apex leads to significant changes in the injected current, which can amount to more than an order of magnitude, and can even change the polarity of the dominant charge carrier. As a direct consequence, the single-particle band gap and band alignment of the organic material can be directly obtained from tip height-voltage (z-V) curves, provided that the tip has a sufficiently sharp apex.

Endgroup and Sidechain Functionalization of Surface-Initiated ROMP Thin Films: Progress Towards ROMP-Based Molecular Wires

2018 ◽  
Author(s):  
Nicholas Marshall
Keyword(s):  
Thin Films ◽  
Contact Angle ◽  
Cyclic Voltammetry ◽  
Polymer Films ◽  
Conjugated Polymer ◽  
Ring Opening ◽  
Molecular Wires ◽  
Metathesis Polymerization ◽  
Cross Metathesis ◽  
Active Ester

A set of experiments in surface-initiated ring-opening metathesis polymerization, including end-functionalization of growing brushes and contact angle/cyclic voltammetry measurements. We report preparation and CV of two different conjugated polymer films, and several endgroup and sidechain functionalization experiments using cross-metathesis and active ester substitution.<br>

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