Porous Polymers from Self‐Assembled Structures

Todd, Eric M.

doi:10.1002/9780470929445.ch2

Cited by 9 publications

(7 citation statements)

References 158 publications

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“…A variety of approaches can be used to generate porous polymers: macromolecular design (porous frameworks, rigid structures with inherent microporosity), porogen incorporation, phase inversion, and templating. − The available templating techniques include block copolymer (BCP) templating, solid particle templating, breath figure templating, and, the focus of this Perspective, emulsion templating. , This Perspective provides an in-depth look at the current state of “emulsion templating”, noting the conceptual breakthroughs that led to the evolution of emulsion templating from a process that had a limited scope to a process that has a continually expanding scope. The original application of emulsion templating was to synthesize hydrophobic cross-linked porous polymer monoliths known as “polyHIPEs”.…”

Section: Introductionmentioning

confidence: 99%

Emulsion Templating: Porous Polymers and Beyond

et al. 2019

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Emulsion templating presently extends far beyond the original hydrophobic porous polymers that were synthesized within surfactant-stabilized water-in-oil high internal phase emulsions (HIPEs) by using free radical polymerization. This Perspective presents the extraordinary versatility of emulsion templating that has emerged with the growing numbers of HIPE systems, HIPE stabilization strategies, monomers, polymerization chemistries, multicomponent materials, and surface functionalities. Emulsion templating now goes far beyond "porous polymers" by encompassing the encapsulation of aqueous solutions, ionic melts, and organic liquids as well as by encompassing porous carbons and porous inorganics. Herein, we present comprehensive pictures of the state-of-the-art, of the prospective large-scale and niche applications, of the advantages and challenges for industrial scale-up, and of the crucial directions that should be pursued in future work. We demonstrate that it is emulsion templating's considerable and versatile parameter space that offers opportunities for pioneering work, breakthrough innovations, scientific/engineering achievements, and industrial adoption.

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Section: Introductionmentioning

confidence: 99%

Emulsion Templating: Porous Polymers and Beyond

et al. 2019

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“…Porous polymers are highly valued materials in separations, catalysis, ion exchange, and templating. , Although inorganic porous media such as metal oxides or silica , have shown long-standing utility, porous organic polymers engender unrivaled opportunities to tune porosity, surface chemistry, structure, and properties through material design and myriad preparative strategies. Such diverse application can also leverage the processability, mechanical integrity, and versatile surface functionality afforded by an organic framework.…”

Section: Introductionmentioning

confidence: 99%

Tuning Mesoporosity in Cross-Linked Nanostructured Thermosets via Polymerization-Induced Microphase Separation

Schulze

Hillmyer

2017

Macromolecules

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Using the synthetic approach of polymerization-induced microphase separation (PIMS), we prepared cocontinuous and cross-linked nanostructured monoliths from bulk polymerizations of styrene and divinylbenzene (DVB) in the presence of polylactide macro-chain-transfer agents (PLA-CTAs). The resulting monolithic precursors were converted to cross-linked mesoporous materials following hydrolytic degradation of the PLA domain, the morphology and porosity of which were characterized through a combination of small-angle X-ray scattering, scanning electron microscopy, and nitrogen sorption experiments. This report highlights the concept, functionality, and limitations of PIMS for the generation of mesoporous materials through variation of reaction parameters found to strongly influence the porous properties of the matrix: the cross-linker-to-monomer ratio, reaction temperature, molar mass and mass fraction of PLA-CTA, and the reactivity of the DVB isomer. Increases in the cross-linker-to-monomer ratio (≥40 mol % DVB) induced formation of smaller mesopores within the matrix in addition to the principal pore mode largely defined by the molar mass and mass fraction of the PLA-CTA. Higher reaction temperatures and the increased relative reactivity of the p-DVB isomer are shown to influence the matrix integrity, ultimately achieving surface areas as high as 796 m2 g–1 using 8 kg mol–1 PLA-CTA. In combination, these parameters suggest methods to circumvent limitations of pore collapse associated with concomitant reductions in the molar mass of PLA-CTA.

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“…Block polymers are a versatile class of materials capable of self-assembly into a number morphologies on nanometer length scales due to covalent linkage of thermodynamically incompatible segments. , Through judicious choice of the chemical structure and functionality of each component, blocks can be selectively degraded and the self-assembled materials can be rendered mesoporous. , To maximize accessibility and connectivity to the envisioned microporous polymer component, the mesopores should percolate throughout the entire material; thus, we required a method that produces a bicontinuous structure with percolating mesopores in a microporous matrix.…”

Section: Introductionmentioning

confidence: 99%

Intrinsically Hierarchical Nanoporous Polymers via Polymerization-Induced Microphase Separation

Larsen

Horn

et al. 2017

Macromolecules

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The synthesis of microporous polymers generally requires postpolymerization modification via hyper-cross-linking to trap the polymeric network in a state with high void volume. An alternative approach utilizes rigid, sterically demanding monomers to inhibit efficient packing, thus leading to a high degree of free volume between polymer side groups and main chains. Herein we combine polymers of intrinsic microporosity with polymerization-induced microphase separation (PIMS), a versatile methodology for the synthesis of nanostructured materials that can be rendered mesoporous. Copolymerization of various styrenic monomers with divinylbenzene in the presence of a poly(lactide) terminated with a chain-transfer agent (PLA-CTA) results in kinetic trapping of a microphase-separated state. Subsequent etching of PLA provides a bicontinuous mesoporous network. Using equilibrium and kinetic nitrogen sorption experiments as well as positron annihilation lifetime spectroscopy (PALS), we demonstrate that variations in the steric characteristics of the styrenic monomer impart the network with microporosity, resulting in hierarchically (meso and micro) porous materials. Additionally, structure–property relationships of the styrenic monomer with total surface area and pore volume indicate that the glass transition temperature (T g) of the corresponding styrenic homopolymers provides a reasonable measure of the steric interactions and resultant microporosity in these systems. Finally, PALS provides insight into micro- and mesoscopic void volume differences between porous monoliths containing either tert-butyl or TMS-modified styrenic monomers compared to the parent, unmodified styrene.

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Porous Polymers from Self‐Assembled Structures

Cited by 9 publications

References 158 publications

Emulsion Templating: Porous Polymers and Beyond

Emulsion Templating: Porous Polymers and Beyond

Tuning Mesoporosity in Cross-Linked Nanostructured Thermosets via Polymerization-Induced Microphase Separation

Intrinsically Hierarchical Nanoporous Polymers via Polymerization-Induced Microphase Separation

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