Hydrophilic macroporous monoliths with tunable water uptake capacity fabricated by water‐in‐oil high internal phase emulsion templating

Abstract

In this contribution, a series of well‐defined amphiphilic di‐block copolymers poly(ethylene oxide)‐b‐polystyrene (PEO43‐b‐PSx) with different PS segment lengths of x = 41, 78, and 130 units were synthesized through activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). The as‐prepared block copolymers successfully stabilized the water‐in‐oil (W/O) high internal phase emulsions (HIPEs) containing pH responsive monomers 2‐(dimethylamino)ethyl methacrylate (DMAEMA) and 2‐(diethylamino)ethyl methacrylate (DEAEMA). The effect of macro‐surfactant loading, PS segment length, and DMAEMA/DEAEMA content on the stability of HIPEs and the corresponding polyHIPE structure were investigated. Results show that the average void size of polyHIPE decreases with the increase of surfactant concentration. Macroporous morphologies with closed‐cell or open‐cell can be manipulated by surfactant loading as well. The openness of polyHIPE decreases as the increase in hydrophobic PS segment length. Compared to DMAEMA containing HIPE systems, stable DEAEMA containing HIPEs are more easily obtained by using the as‐prepared macro‐surfactant. Stable HIPE with a relatively large amount of DEAEMA, up to 70 vol% of oil‐phase has been achieved. The obtained PDEAEMA‐co‐PS polyHIPEs derived from 0.116 mol% PEO43‐b‐PS41 stabilized emulsion templates show pH responsiveness towards water absorption and the highest acidic water uptake capacity can be up to 6.6 times its weight at equilibrium state. This work paves the way for the preparation of hydrophilic macroporous monolith from stable W/O HIPE template, and confirms the strength of macro‐surfactant in such an approach.

Long‐Term Stable Hydrogen Production from Water and Lactic Acid via Visible‐Light‐Driven Photocatalysis in a Porous Microreactor

“…A PP12 microreactor is prepared via polymerization of styrene (St) and 2-(dimethylamino)ethyl methacrylate (DEAEMA), with divinyl benzene (DVB), poly(ethylene oxide) 43 -b-polystyrene 64 (PEO 43 -b-PS 64 ), and 2,2'-azobis(2methylpropionitrile) (AIBN) as cross-linker, surfactant, and initiator, respectively (Figure 1d). [12] It is white, and has a disk shape and a typical polymer matrix, with a diameter of 2.5 cm and a thickness of 0.4 cm (Figure 1c). There are abundant tri-coordinated N atoms and OÀ C=O groups in PP12 (Figure 2a).…”

Polydimethylsiloxane Polymerized Emulsions for Acoustic Materials Prepared Using Reactive Triblock Copolymer Surfactants

“…We attribute this to the poor solubility of the block copolymer surfactants in the mobile phase of the SEC instruments, and this result has also been seen in related reports. 47 We first prepared water-in-PDMS emulsions that had an IP volume fraction of 60% and the triblock surfactant or Silube was added at 1 wt % (with respect to the weight of CP). The PDMS-based continuous phase consists of a mixture of pendent-thiol-and vinyl-terminated polysiloxanes.…”

“…Alternatively, open-cell pore structures can be obtained by using polymeric surfactants and by initiating the polymerization from the CP. Furthermore, tuning of the pore structure has been achieved using block copolymer surfactants with different ratios of hydrophilic to hydrophobic character. , One method to prepare amphiphilic block copolymer surfactants is reversible addition–fragmentation chain transfer (RAFT) polymerizations, , and this method has been used to prepare surfactants for HIPE stabilization. − For example, Debuigne and co-workers synthesized a library of poly­(ethylene oxide)/polystyrene (PEO/PS) block copolymers with different PS contents using RAFT polymerizations to prepare PS/DVB-based polyHIPEs with different degrees of openness. In that work, it was shown that PEO/PS surfactants with equal block ratios obtained the highest degree of openness of ∼10%, and surfactants with the highest PS content obtained the lowest degree of openness of ∼2%.…”

“…Furthermore, tuning of the pore structure has been achieved using block copolymer surfactants with different ratios of hydrophilic to hydrophobic character. 46,47 One method to prepare amphiphilic block copolymer surfactants is reversible addition−fragmentation chain transfer (RAFT) polymerizations, 48,49 and this method has been used to prepare surfactants for HIPE stabilization. 50−52 For example, Debuigne and co-workers 53 synthesized a library of poly(ethylene oxide)/polystyrene (PEO/PS) block copolymers with different PS contents using RAFT polymerizations to prepare PS/DVBbased polyHIPEs with different degrees of openness.…”

Macroporous polyHIPE modified with β-cyclodextrin for the removal of bisphenol A from water

“…ATRP can be adopted to fabricate the polyHIPE platform with functional groups. 53–55 Porous polyHIPEs as the polymerization initiator (inimer) can be decorated with different polymer brushes. PolyHIPEs with a high surface area offer an effective platform for loading β-CD, which could improve the adsorption effect for BPA.…”