A Sponge Morphology in an Elementary Coacervate

Abstract

A zwitterionic gemini surfactant forms a coacervate which is "elementary" in the sense that it consists of a single solute as opposed to the multicomponents (e.g., cetylpyridinium chloride/hexanol/water/NaCl) common in the coacervate literature. The gemini dissolves in water but then quickly separates as oily droplets which, despite the high water content of 83 wt %, are immiscible with water. Cryogenic temperature high-resolution scanning electron microscopy (cryo-HRSEM) examination of the droplets shows a distinct "sponge" structure. Although previously proposed for coacervate phases, a sponge morphology has never before been clearly depicted. The absence of previous electron microscopy (EM) pictures of the coacervate network is attributed to artifacts associated with transmission electron microscopy (TEM) methods, to the fragility of the coacervate toward physical perturbations, and to possible compositional changes with complex mixtures during sample preparation. When the gemini coacervate was exposed to mild shear, the honeycomb structure disappeared and was replaced by a lamellar phase.

Preparation of ureido group bearing polymers and their upper critical solution temperature in water

“…Two aqueous phases are immiscible for the liquid–liquid phase separation state. One is polymer rich phase and another is so‐called equilibrium liquid which is usually polymer poor phase . The polymer rich colloidally stable liquid droplets are called as a coacervate.…”

Coacervates as Prebiotic Reactors

“…Thus, a primitive selection could occur which would favor such coacervates. The coacervate systems have been studied also more recently (Burgess 1990;Burgess et al, 1991;Burgess and Singh 1993;Dubin et al, 2008;Liberatore et al, 2009;Menger 2002Menger , 2011Menger et al, 2000;Menger and Sykes, 1998;McClements et al, 2009;Rabiskova et al, 1994;Singh and Burgess, 1989;Stuart et al, 1998;Wang et al, 1999Wang et al, , 2000, but not in the prebiotic context.…”

Catch and Release of DNA in Coacervate‐Dispersed Gels

“…In ''The Origin of Life'', [1] A. I. Oparin addressed the importance of coacervate droplets as the possible origin of living cells in the primitive sea. Hence, many researchers have focused on the properties of coacervate and its applications, [2][3][4][5][6][7][8][9][10] which have been extensively investigated in diverse fields such as polymer sciences, [7,8] food hydrocolloids [9] and life sciences. [10] Recently, we have found that the polyzwitterion poly [3-(N,N-dimethyl-N-metacryloyloxyammonium)propanesulfonic acid] (PDMAPS), [11][12][13] which has both positive and negative univalent charges on each side group along the polymer chain (Figure 1(a)), has an upper critical solution temperature (UCST) and forms coacervate droplets by itself on cooling.…”