Keping Chen,Neil Grant,Liyun Liang,Haifei Zhang,Bien Tan
Amphiphilic block copolymers poly(ethylene glycol)-block-oligo(vinyl acetate) (PEG-b-OVAc) and OVAc-b-PEG-b-OVAc have been demonstrated to be effective surfactants for CO2-in-water (C/W) emulsions. However, the high cost and difficulty of synthesis process can render the economics of CO2 process unfavorable. In this work, by reversible addition−fragmentation chain transfer (RAFT) polymerization, a series of well-defined CO2-philic triblock copolymers X−OVAc-b-PEG-b-OVAc−X (where X stands for xanthate group) were synthesized. The structures and molecular weights of these copolymers were characterized by 1H NMR and GPC. The results of GPC analysis exhibited relatively narrow polydispersity (PDI < 1.35). The process of preparation of X−OVAc-based surfactants was much more simple, inexpensive and also easy to control, which could promote industrial-scale applications. The X−OVAc-based surfactants were found effectively to produce highly concentrated stable C/W emulsions. Porous emulsion-templated materials were prepared by the polymerization of the continuous phase of C/W emulsions. The open-cell morphology of the emulsion-templated materials was evidenced by scanning electron microscope. To tune the morphology of the porous structures, the influence of the surfactant concentration and molecular weight of OVAc block were also investigated. It was shown that X−OVAc-based surfactants can outperform perfluorinated surfactants and approach OVAc-based surfactants for such applications.
Hemoperfusion (HP) is one of the most prominent therapies for treating uremia, hyperbilirubinemia, and acute drug toxicity. The comprehensive performance of currently used porous HP adsorbents needs to be improved due to the impediment to their synthesis strategy. Herein, green carbon dioxide-in-water high internal phase emulsions (C/W HIPEs) were utilized and emulsified with poly(vinyl alcohol) (PVA) for the formation of a heparin-mimetic chitosan oligosaccharides/poly(acrylamide-co-sodium 4-styrenesulfonate) [COS/P(AM-co-SSS)] monolith, which exhibited good mechanical properties, stable swelling performance, hydrophilic properties, anticoagulant effect, and low hemolysis. It showed a strong toxin adsorption capacity (415.2 mg/g for creatinine, 199.3 mg/g for urea, 279.5 mg/g for bilirubin, and 160 mg/g for tetracycline). The adsorption process of porous COS/P(AM-co-SSS) followed the pseudo-second-order kinetic and Langmuir isotherm models. Moreover, the porous materials had a strong electrostatic force on creatinine. The removal of creatinine by simulated in vitro blood perfusion was 80.2% within 30 min. This work provides a green preparation strategy for developing novel HP materials, highlighting their potential application value in blood and environmental purification.
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