Asymmetrical flow field-flow fractionation as a novel technique for the analysis of PS-b-PI copolymers

Makan, Ashwell C.; Sinha, Pritish; Ngaza, Nyashadzashe; Aswegen, Werner van; Pasch, Harald

doi:10.1007/s00216-013-7225-2

Cited by 6 publications

(4 citation statements)

References 25 publications

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“…[ 7 ] ThFFF can thus fractionate analytes according to size ( D ) as well as chemical composition ( D T ) and, as a consequence, has been applied to the characterization of a variety of polymers. [ 8,9 ] The capabilities of ThFFF in separating polymers according to tacticity and microstructure have been discussed recently. [ 2,3 ] The infl uence of solvent composition on polymer retention behavior has been extensively studied and it was demonstrated that solvent composition, as well as viscosity, can have a signifi cant infl uence.…”

Section: Fractionation Of Poly(butyl Methacrylate) By Molecular Topol...mentioning

confidence: 99%

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Fractionation of Poly(butyl methacrylate) by Molecular Topology Using Multidetector Thermal Field‐Flow Fractionation

Greyling

Pasch

2015

Macromol. Rapid Commun.

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Thermal field-flow fractionation (ThFFF) is an interesting alternative to column-based fractionation being able to address different molecular parameters including size and composition. Until today it has not been shown to be able to fractionate polymers of similar molar masses and chemical compositions by molecular topology. The present study demonstrates that poly(butyl methacrylates) with identical molar masses can be fractionated by ThFFF according to the topology of the butyl group. The influence of the solvent polarity on the thermal diffusion behavior of these polymers is presented and it is shown to have a significant influence on the fractionation of poly(n-butyl methacrylate) and poly(t-butyl methacrylate). Fractionation improves with increasing solvent polarity and solvent polarity may have a greater influence on fractionation than solvent viscosity. It is found that the thermal diffusion coefficient, D(T), as well as the hydrodynamic diameter, D(h), exhibit increasing trends with increasing solvent polarity. The solvent quality has a significant influence on the fractionation. It is found that cyclohexane, being a theta solvent for poly(t-butyl methacrylate) but not for poly(n-butyl methacrylate), significantly improves the fractionation of the samples by decreasing the diffusion rate of the former but not the latter.

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Section: Fractionation Of Poly(butyl Methacrylate) By Molecular Topol...mentioning

confidence: 99%

“…Furthermore, D is dependent on the size of the analyte in solution, whereas D T is dependent on the chemical nature of the analyte and the solvent . ThFFF can thus fractionate analytes according to size ( D ) as well as chemical composition ( D T ) and, as a consequence, has been applied to the characterization of a variety of polymers …”

Section: Introductionmentioning

confidence: 99%

Fractionation of Poly(butyl methacrylate) by Molecular Topology Using Multidetector Thermal Field‐Flow Fractionation

Greyling

Pasch

2015

Macromol. Rapid Commun.

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“…molecular weight and polydispersity) of the BCP. 28,29,42,43 In this work, we present the application of BCP chromatographic fractionation to create tailored inorganic mesoporous thin films. Crucially, we identify the role of molecular weight, composition and dispersity on the resulting pore size distribution.…”

Section: Introductionmentioning

confidence: 99%

Fractionation of block copolymers for pore size control and reduced dispersity in mesoporous inorganic thin films

et al. 2020

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“…molecular weight and polydispersity) of the BCP. [40][41][42][43] In this work, we present the application of BCP chromatographic fractionation to create tailored inorganic mesoporous thin films. Crucially, we identify the role of molecular weight, composition and dispersity on the resulting pore size distribution.…”

Section: Introductionmentioning

confidence: 99%

Fractionation of Block Copolymers for Pore Size Control and Reduced Dispersity in Mesoporous Inorganic Thin Films

Fernandez¹,

Reid²,

Suthar³

et al. 2020

Preprint

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Mesoporous inorganic thin films are promising materials architectures for a variety of applications, including sensing, catalysis, protective coatings, energy generation and storage. In many cases, precise control over a bicontinuous porous network on the 10-nm length scale is crucial for their operation. A particularly promising route for structure formation utilizes block copolymer (BCP) micelles in solution as sacrificial structure-directing agents for the co-assembly of inorganic precursors. This method offers pore size control via the molecular weight of the pore forming block and is compatible with broad materials library. On the other hand, the molecular weight dependence impedes continuous pore tuning and the intrinsic polymer dispersity presents challenges to the pore size homogeneity. To this end, we demonstrate how chromatographic fractionation of BCPs provides a powerful method to control the pore size and dispersity of the resulting mesoporous thin films. We apply a semi-preparative size exclusion chromatographic fractionation to a polydisperse poly(isobutylene)-block-poly(ethylene oxide) (PIB-b-PEO) BCP obtained from scaled-up synthesis. The isolation of BCP fractions with distinct molecular weight and narrowed dispersity allowed us to not only tune the characteristic pore size from 9.1±1.5 to 14.1±2.1 nm with the identical BCP source material, but also significantly reduce the pore size dispersity compared to the non-fractionated BCP. Our findings offer a route to obtain a library of monodisperse BCPs from a polydisperse feedstock and provide important insights on the direct relationship between macromolecular characteristics and the resulting structure-directed mesopores, in particular related to dispersity.

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Asymmetrical flow field-flow fractionation as a novel technique for the analysis of PS-b-PI copolymers

Cited by 6 publications

References 25 publications

Fractionation of Poly(butyl methacrylate) by Molecular Topology Using Multidetector Thermal Field‐Flow Fractionation

Fractionation of Poly(butyl methacrylate) by Molecular Topology Using Multidetector Thermal Field‐Flow Fractionation

Fractionation of block copolymers for pore size control and reduced dispersity in mesoporous inorganic thin films

Fractionation of Block Copolymers for Pore Size Control and Reduced Dispersity in Mesoporous Inorganic Thin Films

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