Determination of interaction parameters of block copolymers containing aromatic polyesters from solubility parameters obtained from solution viscosities

Diblock copolymers (BCP) with poly(methyl methacrylate) and poly(1H,1H,2H,2H-perfluorodecyl methacrylate) (PsfMA) blocks prepared by anionic polymerization in tetrahydrofuran at −78 °C and atom transfer radical polymerization (ATRP) at 60 °C, respectively, with stepwise varied composition over a wide range in the phase diagram are compared with respect to synthesis limits, phase separation behavior in bulk, and properties of thin films. Both methods yield BCPs with low dispersity (1.1-1.2) at molar masses below 100 kg mol −1 . Higher semifluorinated contents can be achieved by ATRP in 1,3-bis(trifluoromethyl)benzene which ensured solubility of PsfMA. BCPs obtained by anionic polymerization show a more distinct phase separation, that is, more regular nanostructures. Additionally, self-organization of the semifluorinated side chains occurs generating smectic layers which alters in turn the BCP morphology especially in thin films as compared to non-semifluorinated BCP. All BCPs show amphiphilic behavior and form micelles in organic solvents which can be used to deposit nanoparticles. periodic structures is the low dispersity − D of both blocks in the BCP which can mostly be achieved by employing controlled polymerization conditions. Although more and more methods of controlled polymerizations appear, such as light-controlled polymerization of methacrylates to BCP in a one-pot procedure, [7] visible-light polymerization from hyperbranched poly(methyl methacrylate) macroinitiators catalyzed by Mn 2 (CO) 10 , [8] combination of polymerization and click chemistry, and many others, and taking the variety of BCP syntheses results reported into account, standard techniques for BCP synthesis as anionic polymerization and atom transfer radical polymerization (ATRP) still appear to be the most successful with regards to achieving low dispersity and high control over the structure and molar mass.In this study, we want to compare diblock copolymers with a poly(methyl methacrylate) (PMMA) and a

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“…The solubility parameter δ was determined by Fedors increment approach . Applying formula (see also ref

χ_{AB} (T) = (V_{A} + V_{B}) / (2 R T) \times {(δ_{normalA} - δ_{normalB})}^{2}

…”

Section: Methodsmentioning

confidence: 99%

Semifluorinated PMMA Block Copolymers: Synthesis, Nanostructure, and Thin Film Properties

Pospiech

Jehnichen

Eckstein

et al. 2017

Macro Chemistry & Physics

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“…Since polymers usually degrade before vaporization, their vaporization energy cannot be measured. There are several ways to determine the solubility parameters despite this constraint . In this work, they were estimated by an increment method according to van Krevelen .…”

Section: Calculation Of Surface‐free Energy Solubility and Interactmentioning

confidence: 99%

“…In this work, they were estimated by an increment method according to van Krevelen . The polymers were subdivided in molecule fragments consisting of different functional groups as described by Pospiech et al The solubility parameters of the polymers were obtained by:

δ_{i} = \sqrt{\frac{\sum E_{fragment}^{coh}}{\sum V_{fragment}}}

…”

Section: Calculation Of Surface‐free Energy Solubility and Interactmentioning

confidence: 99%

“…The interaction parameter χ AB of two compounds was defined by Flory to describe the energetic interaction between polymers and solvents or different polymers semi‐empirically. These parameters have been used to predict, for example, the miscibility and phase separation of polymer mixtures or block copolymers or the miscibility of hydrophobically modified nanoparticles with different solvents . Experimental and theoretical studies tried to establish a relation among the dispersion of modified clay platelets in polymers, the solubility parameters of the polymers, and the interaction parameters of the systems.…”

Section: Introductionmentioning

confidence: 99%

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Nanoparticle Distribution in Three‐Layer Polymer–Nanoparticle Composite Films: Comparison of Experiment and Theory

Bunk

Drechsler

Friedel

et al. 2014

Part & Part Syst Charact

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The distribution of hydrophobic nanoparticles deposited on a hydrophilic polymer film is investigated by scanning electron microscopy, transmission electron microscopy, and atomic force microscopy before and after spin‐coating a polymer solution on the particle film and drying it at room temperature. Various polymers and solvents are used. To reach equilibrium, all investigated systems are annealed additionally above the glass transition temperature (Tg) of the polymers. The compatibility of the interacting components is estimated by calculating their surface energy, solubility, and mutual interaction parameters. The experimental results show a redistribution of the particles on both interfaces of the polymer film. This corresponds to the calculated immiscibility of particles and polymers. The distribution of the nanoparticles at the interfaces is related mainly to the vapor pressure of the solvent, that is, kinetic effects during spin‐coating. Only minor contributions result from surface energy, solubility, and interaction parameters.

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“…48 This corresponds to χ = 1.5 for this polymer pair, a high value indicating they will be immiscible. 51,52 We have verified microphase separation by differential scanning calorimetry (DSC) of the copolymer and relevant homopolymers ( Figure 2a). PVDF-g-PEGPEA shows a glasstransition temperature (T g ) of ∼13°C, matching that observed for PEGPEA homopolymer.…”

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confidence: 95%

Nanoconfinement and Chemical Structure Effects on Permeation Selectivity of Self-Assembling Graft Copolymers

2015

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Permeation of small molecule solutes through thin films is typically described by the solution-diffusion model, but this model cannot predict the effects of nanostructure due to self-assembly or additives. Other models focusing on diffusion through isolated nanopores indicate that confining permeation to channels slightly larger than the size of the solute can lead to an increased influence of solute−pore wall interactions on permeation rate. In this study, we analyze how differences in polymer nanostructure affect the relative contributions of solute size and polymer−solute interactions on transport rate. We compared the diffusion rates of several small molecules through two polymer thin films: A cross-linked, homogeneous film of poly(ethylene glycol phenyl ether acrylate) (PEGPEA) and a graft copolymer with a poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-co-CTFE)) backbone and PEGPEA side chains that self-assemble into continuous ∼1−3 nm PEGPEA domains through which transport occurs. We correlated these rates with the size of each solute and its chemical affinity to PEGPEA, as measured by the difference between their solubility parameters. Diffusion rate through the homogeneous polymer film was controlled by solute size, whereas diffusion rate through the copolymer was strongly controlled by the difference between the solubility parameters. Furthermore, permeation selectivity between two selected molecules was 2.5× higher for the nanostructured copolymer, likely enhanced by the nanoconfinement effects. These initial results indicate that polymer self-assembly is a promising tool for designing polymeric membranes that can differentiate between solutes of similar size but differing chemical structures. R egulating permeation through materials is crucial for many applications, including selective membranes, controlled drug delivery, and packaging. 1−7 Permeation selectivity is especially critical in membrane separations. Membranes that are capable of separating small molecules of similar size by their chemical structure can potentially have great impact in drug manufacture 8−10 and the petrochemical industry. A better understanding of how to modulate the permeation of small molecules through polymers by manipulating chemical interactions and nanostructure can open up new avenues to such membranes.Most current membrane selective layers are homogeneous polymers 11−13 where permeation is described by the solutiondiffusion model. The solute dissolves in the polymer on the feed side, diffuses, and desorbs into the permeate. The molar flux J A of solute A through the polymer film is given bywhere S A , D A , and P A are the solubility, diffusivity, and permeability of A in the polymer, respectively, z is the polymer film thickness, and ΔC A is the concentration difference between the feed and permeate. The permeability of a solute increases with increasing solubility in the polymer and decreasing solute size. This model works well for most gas separation membranes 11−14 and has been adapted for desalinatio...

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Determination of interaction parameters of block copolymers containing aromatic polyesters from solubility parameters obtained from solution viscosities

Cited by 26 publications

References 2 publications

Semifluorinated PMMA Block Copolymers: Synthesis, Nanostructure, and Thin Film Properties

Semifluorinated PMMA Block Copolymers: Synthesis, Nanostructure, and Thin Film Properties

Nanoparticle Distribution in Three‐Layer Polymer–Nanoparticle Composite Films: Comparison of Experiment and Theory

Nanoconfinement and Chemical Structure Effects on Permeation Selectivity of Self-Assembling Graft Copolymers

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