Stimuli-Responsive Nanolatexes: Porating Films

Abstract

Nanolatex Synthesis and CharacterizationOur nanolatexes were prepared via microemulsion polymerization, a special type of dispersion polymerization, from aqueous acrylate/methacrylate microemulsions stabilized by reactive ionic liquid surfactants. To exemplify our process we used methylmethacrylate (MMA) as a comonomer along with the ionic liquid reactive acrylate surfactant 1-(11acryloyloxyundecyl)-3-methylimidazolium bromide (ILBr) to compose the nanolatex precursor solution (microemulsion). ILBr was prepared as described in Refs. 11, 17, and 26 of the main text. This monomer contains an approximately 1% cross-linker, 1,3-bis(11acryloyloxyundecyl)imidazolium bromide as a preparative impurity from alkyl group scrambling in the quaternization step. Ionic liquids are defined as salts, mostly organic, that melt below 100°C; ILBr melts at about 50°C. Microemulsion PolymerizationA partial ternary phase diagram of this system is illustrated in Fig. S1, where one of the compositions for microemulsion polymerization we utilized is indicated by the "✕" in the lower left corner. The microemulsion domain is a thermodynamically stable and somewhat exotic single phase solution. In the illustrated domain, MMA swollen micelles of ILBr are the most prevalent complexes, although irregular bicontinuous microstructure exists at higher surfactant levels.The latexes were prepared by diluting a stock solution of 60% ILBr (w/w) in MMA with the appropriate amounts of water to reach a total volume of 25 ml for each composition. AIBN initiator was present in the MMA stock solution at 0.5% (w/w) with respect to total monomer weight. The clear microemulsion solutions were then heated overnight at 60 °C in a temperature controlled bath.The compositions ranging from 2 -4% ILBr content showed an increasing presence of a light blue Tyndall haze. This increasing blue haze indicated particles were present and that a dispersion had formed. Another indicator of particle formation was the increasing suspension viscosity with increasing ILBr/MMA content.Portions of each sample were dialyzed against daily changes of deionized water for three days in order to remove unreacted monomer. Dialysis was performed by placing approximately 1.5 ml of latex sample inside a 7 cm piece of regenerated cellulose dialysis

Advanced Nanocarbon Materials Facilitated by Novel Stimuli-responsive Stabilizers

“…These stabilizers are stimuli responsive to various anions, 3,11 and iodide interacts with the imidazolium ring more strongly than bromide. The Hofmeister series for destabilization of these nanolatexes decreases in the order:…”

“…2 It has been shown that IL monomers based on imidazolium salts exhibit anion stimuli responsiveness spanning 4 orders of magnitude in sensitivity in aqueous systems. 3 Important potential applications of ILs and PILs have been provided by Aida and Fukushima 4 and by Ohno and others, 5 particularly in application to nanocarbon materials. In this report we demonstrate how to focus similar approaches upon waterborne nanocarbon dispersions using PILs and further how to make advanced materials from such waterborne dispersions.…”

“…The destabilization afforded by the dilute iodide induces slow 2D aggregation and platelet growth. The mechanism of destabilization is one that transformes these nanolatexes from being ideal stabilizers, osmotic nanospheres, 3 to contracted polymeric surface domes exhibiting only attractive van der Waals forces upon collision with graphene sheets. We believe radial growth in 2D occurs by overlapping very small graphene sheets and that slow gowth in thickness also occurs by this "overlapping" layering.…”

Structural evolution of imidazolium-based poly (ionic liquid) assemblies during solvent evaporation

“…The corresponding 2D SAXS images (Figure 5b) display a broad and isotropic ring, suggesting the emergence of a weakly ordered morphology without long-range periodicity (Figure 5d). This morphology can be further confirmed by POM, in which a very weak optical birefringence is observed (Figure 5c) [36], which reduces the chain mobility, and hence hinders the ordering packing of PIL molecules. ] samples were thoroughly dried in vacuum at 80°C for at least 24 hours.…”

Organosiloxane Supramolecular Liquids—Surface‐Energy‐Driven Phase Transitions

“…[18,19] These osmotic spheroids constitute the second reported example of such objects. A nanogel/nanolatex that coalesces upon drying (not a nanofluid) was recently cited [20] as the first experimentally realized example of osmotic spheres. .…”