Self-organization in precipitation reactions far from the equilibrium

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Science Advances  19 Aug 2016:
Vol. 2, no. 8, e1601144
DOI: 10.1126/sciadv.1601144


  • Fig. 1 Chemical gardens.

    (A to C) Schematics of experiments using (A) a seed crystal, (B) solution injection, and (C) a spatially confined system. (D) Typical example of chemical gardens. (E) Hydrothermal vent at Lost City [adapted with permission from Kelly et al. (51)]. (F) Cu(OH)2 tube formed by solution injection method [adapted with permission from Baker et al. (64)]. (G and H) Microtube from reactant-loaded polymer beads that develop rim structures (arrow). (I) Microtubes from a polyoxometalate (POM) precipitation reaction [adapted with permission from Cooper et al. (45)]. (J and K) Emission spectrum (J) and transmission electron microscopy (K) image of quantum dot (QD)–functionalized zinc oxide/hydroxide tubes [adapted with permission from Makki et al. (34)]. (L) Postsynthetic processing of copper hydroxide tube to produce various copper-based materials [adapted with permission from Uechi et al. (72)]. (M to O) Thin-layered chemical gardens of (M and O) cobalt hydroxide [adapted with permission from Batista et al. (73)] and (N) cobalt oxalate [adapted with permission from Roszol et al. (75)]. (P) Scaling law reveals logarithmic spiral shapes [adapted with permission from Haudin et al. (35)]. (Q) Precipitate membranes formed by double injection in microfluidic device [adapted with permission from Batista and Steinbock (83)].

  • Fig. 2 Silica-carbonate biomorphs.

    (A to C) Schematics of experimental setups: (A) gel-solution, (B) gas diffusion, and (C) single-phase methods. (D to I) Optical micrographs of biomorphs showing (D) leaf (false coloring), (E) double helix, (F) single helix or worm, (G) wavy curtain, (H) micro-urn, and (I) funnel structures. (J) Coaligned nanorods that constitute the biomorph structures [D to J; adapted with permission from Nakouzi et al. (91)]. (K to N) Stages of biomorph growth from (K) rod, to (L) globule, (M) sheet, and, eventually, (N) double helix [adapted with permission from García-Ruiz et al. (85)]. (O) Periodic height variations along the biomorph sheet surface due to nanorod alignment waves observed in SEM and AFM [adapted with permission from Nakouzi et al. (105)]. (P and Q) Catalytic reactions with gold-functionalized biomorphs: (P) UV-visible spectra showing reduction of p-nitrophenol by NaBH4 and (Q) scheme of surface-catalyzed reactions [adapted with permission from Opel et al. (117)]. A, absorbance.

  • Fig. 3 Periodic precipitation.

    (A to C) Schematics of experiments in (A) one-dimensional tubes, (B) two-dimensional slabs, and (C) using the wet stamping technique. (D and E) Comparison of Liesegang patterns in the (D) traditional and (E) wet stamping setups. (F to J) Assortment of precipitation micropatterns in (F and G) Ag+/Cr2O72−, (H and I) Ag+,Pb2+/Cr2O72− [D to I; adapted with permission from Bensemman et al. (33)], and (J) Ag+/citrate systems [adapted with permission from Nabika et al. (150)]. (K) Controlled precipitation of Ag2Cr2O7 microwrinkles with linearly increasing height [adapted with permission from Walliser et al. (145)]. (L) Periodic precipitation setup for nanoparticle aggregation [adapted with permission from Lagzi et al. (149)].

  • Fig. 4 Dynamic precipitation-dissolution patterns.

    (A to C) Schematics of various experimental setups. (D) Irregular band spacing in the Co(OH)2/Ni(OH)2 precipitation-redissolution system [adapted with permission from Msharrafieh and Sultan (163)]. (E to G) Precipitation pulses (E), distorted fronts (F) [adapted with permission from Volford et al. (165)], and spiral patterns (G) in Al(OH)3 system [adapted with permission from Volford et al. (166)]. (H) Pattern selection in the aluminum hydroxide system as a function of reactant ion concentration [adapted with permission from Dúzs et al. (171)]. (I) Cusp-like front in HgI2 system [adapted with permission from Ayass and Al-Ghoul (173)]. (J) Diagonal feature in a downward propagating front observed experimentally (J) and in simulations (K) [adapted with permission from Tinsley et al. (170)].


  • Table 1 Qualitative comparison of the four classes of precipitation reactions discussed in this review.

    The classical pattern size refers to the length scales one encounters in the typical experiment, but deviations usually exist in specialized cases (see text).

    Chemical gardensBiomorphsLiesegang bandsPrecipitation pulses
    precipitation reactions
    Thermodynamic driving
    Interfacial reactionsGlobal supersaturationLocal supersaturationLocal supersaturation and
    Typical reactantsVery diverseBaCl2, SrCl2, or CaCl2 and
    Na2SiO3, CO2/Na2CO3
    Very diverseAlCl3 or ZnCl2 and NaOH, HgCl2,
    and NaI
    Dominant macroshapeHollow tubesSheets and helicesBands of crystalsPlanar fronts and spirals
    Classical pattern size1 mm (tube radius),
    1 dm (tube length)
    1 μm (sheet height),
    20 μm (helix width)
    1 mm (band spacing)0.1 mm (pulse width),
    1 mm (spiral pitch)
    Typical initial conditionCrystal seed or injectionHomogeneous solution or influx
    of gas
    Solution over gel in tubeSolution over gel in Petri dish
    Amorphous/nanocrystalsPolycrystalline and aligned
    Colloids to macrocrystalsColloids to
    Present in natureHydrothermal vents and
    Possibly (pseudofossils)Layered intrusions and
    Mathematical modelsOnly for specific featuresNoAdvancedAdvanced

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