Building Supracolloidal Fibers from Zwitterion‐Stabilized Adhesive Emulsions

Abstract

Oil-in-water droplets stabilized with polymer zwitterions (PZWs) exhibit salt-responsive aggregationdisaggregation behavior. In this paper, we describe a method to shape these droplets, starting from their aggregated state, into supracolloidal fibers by simply extruding them into aqueous media. The effect of salt concentration, in both the initial emulsion and the aqueous media, on the ability of the emulsions to form fibers is examined. After fiber formation, a transition from well-defined macroscopic fibers to non-interacting droplet dispersions can be triggered, simply by increasing the salt concentration of the aqueous environment. The inter-droplet energy of adhesion and emulsion rheology correlate qualitatively with salt concentration and thus impact the ability of the emulsions to be shaped by extrusion. The inter-droplet adhesion is dependent on both salt concentration and polymer composition, which allows tailoring of conditions to trigger fiber disaggregation. Finally, fibers with variable compositions along their length are prepared by sequential loading and extrusion of emulsions containing oil phases of differing densities.Received: ((will be filled in by the editorial staff))Revised: ((will be filled in by the editorial staff))

Wet‐spun porous fibers from high internal phase emulsions: Continuous preparation and high stretchability

“…A high ammonia concentration over 8.1 mol L −1 , however, tended to degrade the as‐formed polyHIPE fibers. The formation of polyHIPE fibers was different from the previously reported HIPE‐based fibers, 15–16,22 which were formed from aggregation of polymers and/or HIPE stabilizers.…”

“…The densities of the dry WF‐14, WF‐17 and WF‐18 were 0.23, 0.26 and 0.29 g cm −3 , respectively, and the relatively low density indicated the presence of porous structures. HIPE‐based fibers have been obtained from reactive HIPEs, 15,22 but these fibers were usually only stable in some specific aqueous solutions due to the ionic interaction. Unlike these reported fibers from reactive emulsions, the WF‐ X s were stable enough to have liquids removed.…”

“…Different from conventional HIPE‐based fibers which tended to dissolve, 15,22 the dry WF‐ X s were stable by immersing them in various aqueous solutions with different pHs (from 1 to 12) and different saturated salt solutions, such as NaCl, Na 2 SO 4 and Na 2 CO 3 (Figure S3). The high stability was confirmed by the preservation of appearance of the WF‐ X s after immersing in these solutions, and the stability should result from the chemical crosslinking between OEGDA and PEMP.…”

“…The fibers were formed by aggregating emulsion droplets under acidic conditions, and could redisperse into droplets under neutral or alkaline conditions. Supracolloidal fibers have also been prepared from zwitterion‐stabilized adhesive emulsions, 22 and the formation of emulsion‐based fibers is reversible. Fake et al recently reported the fabrication of polyHIPE fibers by extruding water‐in‐oil HIPEs into an aqueous bath containing initiators, and by subsequently polymerizing the HIPEs at 85 to 95°C for 20 min 23 .…”

Zwitterionic Polymer‐Grafted Superhydrophilic and Superoleophobic Silk Fabrics for Anti‐Oil Applications

“…[ 25 ] The strong polarity gives rise to a hydration layer around the zwitterionic polymer chains, [ 26,27 ] which can prevent the adsorption of oil droplets onto the polymer surfaces. [ 28 ] Studies have reported that copolymer hydrogels prepared by poly(ethylene glycol)diacrylate (PEGDA) and zwitterionic monomer, such as carboxybetaine methacrylate and sulfobetaine methacrylate (SBMA), demonstrate better hydrophilicity than those of PEGDA. [ 29,30 ] Most of the zwitterionic materials are coated onto the surface of various substrates to enhance the hydrophilicity.…”