Incorporation Of Water Molecules Research Articles

Noncovalent interactions in N-methylurea crystalline hydrates

Abstract Urea and its derivatives play a significant role in modern organic chemistry and find application in various fields. This study presents the results of investigations of N-methylurea crystalline hydrates. Initial N-methylurea and its crystalline hydrates have been examined by FTIR spectroscopy and X-ray diffraction analysis. It has been found that the incorporation of water molecules into N-methylurea crystals leads to a shift of intensity peaks in both the FTIR spectra and X-ray diffraction patterns. Methylurea crystalline hydrates in the gaseous phase have been additionally explored within the density functional theory at the B3LYP/6-31+G(d,p) level and the theory of atoms in molecules. The nature of water and methylurea molecular interactions via hydrogen bonds have been studied using the electron localization function and noncovalent reduced density gradient. The thermodynamic and nonlinear optical properties of methylurea crystalline hydrate have been determined. The atoms in molecules, electron localization functions, and localized orbital locator topological analyses have been carried out to elucidate the nature of hydrogen bonds in methylurea crystalline hydrates.

Atomic-Scale Insights into Morphological, Structural, and Compositional Evolution of CoOOH during Oxygen Evolution Reaction

Co-based electrocatalysts are an emerging class of materials for the oxygen evolution reaction (OER). These materials undergo dynamic surface changes, converting to an active Co oxyhydroxide (CoOOH) layer during OER. A better understanding of the structural, morphological, and elemental evolution of CoOOH formed during OER is, therefore, crucial for the optimization of Co-based electrocatalysts. Herein, we propose an innovative multimodal method, which combines X-ray photoelectron spectroscopy, electron backscatter diffraction, high-resolution transmission electron microscopy, and atom probe tomography with electrochemical testing to investigate the temporal evolution of the oxidation state, thickness, morphology, and elemental distribution of the CoOOH layer grown on Co(0001) during OER. We reveal that the oxyhydroxide layer with the highest OER activity is a 5−6 nm thick, strongly hydrated film resembling a β-CoOOH(0001) structure and consisting of stacks of nanocrystals; which explains the X-ray amorphous characteristics of active species formed on Co-based electrocatalysts observed by operando X-ray-based techniques. The large interfacial area at these hydrated β-CoOOH(0001) nanocrystals enables efficient mass transport of reacting hydroxyl ions to catalytically active sites, and thus, high OER rates. As OER proceeds, the well-hydrated β-CoOOH(0001) nanocrystals grow into a monolithic crystalline β-CoOOH(0001) film. This goes along with a decrease in water content and electrochemically accessible catalyst area, resulting in slightly decreased OER currents. Overall, our study unprecedentedly unveils that in situ generated thin β-CoOOH(0001) layer undergoes dynamic morphological and elemental changes along with (de)incorporation of water molecules and hydroxyl groups during OER, which in turn alters OER performance. We demonstrate the strength of our multimodal characterization approach when seeking mechanistic insights into the role of structural and compositional evolution of hydrous oxides in activity during electrocatalytic reactions.

Vapoluminescence hysteresis in a platinum(II) salt-based humidity sensor: Mapping the vapochromic response to water vapor

In an effort to address the scarcity of chemical sensors that can record precise, reproducible, and sensitive changes in humidity, this work reports a reversible system based on a coordinatively unsaturated, square-planar platinum(II) salt, [Pt(tpy)Cl]ClO4 (tpy = 2,2′6′,2″-terpyridine). The sensing methodology relies on humidity induced vapochromic/vapoluminescent behavior of the salt; the anhydrous form is yellow in color and demonstrates orange-yellow luminescence indicating weak intermolecular Pt•••Pt interactions. Exposure to water vapor changes the salt color to dark red and the luminescence to red; this is triggered by incorporation of water molecules in the crystal lattice. This reorganizes the crystal packing, and extends Pt•••Pt interactions, as verified by crystal structure. The conversion between the fully hydrated and the fully dehydrated end products are spectroscopically reversible, demonstrating recyclability across cycles. However, the vapoluminescence response trajectory of the dehydrated form to water vapor sorption does not exactly reverse trace the desorption profile of the hydrated form but shows a hysteresis effect, demonstrating the vapochromic journey to be equally important as the destination. This methodology serves as the basis of humidity sensing for both powder as well as crystalline samples. The proposed sensor demonstrates a large linear operational range of humidity sensing (10–80% for crystals) and a limit of detection of 3.3%. The crystals also demonstrate an ability to sense water vapor in the presence of interfering organic vapors. The work presents a new simple, economic and scalable method for humidity sensing.

Enhancing Photoluminescence Quantum Yield in 0D Metal Halides by Introducing Water Molecules

AbstractEnhancing photoluminescence quantum yield (PLQY) is one of the most important issues in photoluminescent materials. Herein, a molecule design strategy to improve the PLQY in 0D metal halides is proposed. Two new lead‐free organic–inorganic metal halide hybrids with broadband orange emissions have been prepared with a PLQY increase of 57% from (C6N2H16)SbCl5 (I) to (C6N2H16)SbCl5⋅H2O (II) by introducing H2O molecules. These two compounds have very similar inorganic frameworks, except that the incorporation of water molecules in II increases the distance between the [SbCl5] polyhedra. It is revealed that the increase of PLQY is mainly attributed to the generation of more local photoelectrons resulting from the additional water molecules. This work provides a new insight to improve the PLQY for 0D environmentally friendly organic–inorganic metal halide hybrids and is beneficial for further photoluminescent material exploration.

H2O incorporation in the phosphorene/a-SiO2 interface: a first-principles study

Based on first-principles calculations, we investigate (i) the energetic stability and electronic properties of single-layer phosphorene (SLP) adsorbed on an amorphous SiO2 surface (SLP/a-SiO2), and (ii) the further incorporation of water molecules at the phosphorene/a-SiO2 interface. In (i), we find that the phosphorene sheet binds to a-SiO2 through van der Waals interactions, even in the presence of oxygen vacancies on the surface. The SLP/a-SiO2 system presents a type-I band alignment, with the valence (conduction) band maximum (minimum) of the phosphorene lying within the energy gap of the a-SiO2 substrate. The structure and the surface-potential corrugations promote the formation of electron-rich and electron-poor regions on the phosphorene sheet and at the SLP/a-SiO2 interface. Such charge density puddles are strengthened by the presence of oxygen vacancies in a-SiO2. In (ii), because of the amorphous structure of the surface, we consider a number of plausible geometries for H2O embedded in the SLP/a-SiO2 interface. There is an energetic preference for the formation of hydroxyl (OH) groups on the a-SiO2 surface. Meanwhile, in the presence of oxygenated water or interstitial oxygen in the phosphorene sheet, we observe the formation of metastable OH bonded to the phosphorene, and the formation of energetically stable P–O–Si chemical bonds at the SLP/a-SiO2 interface. Further x-ray absorption spectra simulations are performed, which aim to provide additional structural/electronic information on the oxygen atoms forming hydroxyl groups or P–O–Si chemical bonds at the interface region.

Synthesis and Characterization of PLGA Shell Microcapsules Containing Aqueous Cores Prepared by Internal Phase Separation.

The preparation of microcapsules consisting of poly(D,L-lactide-co-glycolide) (PLGA) polymer shell and aqueous core is a clear challenge and hence has been rarely addressed in literature. Herein, aqueous core-PLGA shell microcapsules have been prepared by internal phase separation from acetone-water in oil emulsion. The resulting microcapsules exhibited mean particle size of 1.1 ± 0.39μm (PDI = 0.35) with spherical surface morphology and internal poly-nuclear core morphology as indicated by scanning electron microscopy (SEM). The incorporation of water molecules into PLGA microcapsules was confirmed by differential scanning calorimetry (DSC). Aqueous core-PLGA shell microcapsules and the corresponding conventional PLGA microspheres were prepared and loaded with risedronate sodium as a model drug. Interestingly, aqueous core-PLGA shell microcapsules illustrated 2.5-fold increase in drug encapsulation in comparison to the classical PLGA microspheres (i.e., 31.6 vs. 12.7%), while exhibiting sustained release behavior following diffusion-controlled Higuchi model. The reported method could be extrapolated to encapsulate other water soluble drugs and hydrophilic macromolecules into PLGA microcapsules, which should overcome various drawbacks correlated with conventional PLGA microspheres in terms of drug loading and release.

Surface Effects on the Crystallization of Ritonavir Glass

In our previous study, initiation time of crystallization was shown to be basically expressed as a function of only the reduced temperature, which was a ratio of storage and glass transition temperatures. This conclusion was obtained using quenched glasses with minimized surface area stored under a dried atmosphere. In this study, the surface effects on the crystallization were investigated using freeze-dried ritonavir (RTV) glass. Although quenched RTV glass exhibited exceptionally long initiation time, the initiation was accelerated by using the freeze-dried glasses. Storage of the samples under humid conditions further accelerated the crystallization. These surface effects eliminated the energetic barrier for nucleation, and the RTV glass exhibited universal initiation time. In contrast, subsequent crystal growth was slower for the freeze-dried glasses relative to the quenched one, presumably because of less condensed and porous structures that would suppress molecular cooperativity. Storage under a humid atmosphere also appeared to inhibit the crystal growth, presumably because of disruption of the molecular network by water. These findings support the existence of the universal initiation time for crystallization and indicated the importance of surface effects in crystallization behavior. Also, the suppression of crystal growth because of the void structure and incorporation of water molecules were indicated.

A complementary experimental and computational study of loxapine succinate and its monohydrate

The crystal structures of loxapine succinate [systematic name: 4-(2-chlorodibenzo[b,f][1,4]oxazepin-11-yl)-1-methylpiperazin-1-ium 3-carboxypropanoate], C18H19ClN3O(+)·C4H5O4(-), and loxapine succinate monohydrate {systematic name: bis[4-(2-chlorodibenzo[b,f][1,4]oxazepin-11-yl)-1-methylpiperazin-1-ium] succinate succinic acid dihydrate}, 2C18H19ClN3O(+)·C4H4O4(2-)·C4H6O4·2H2O, have been determined using X-ray powder diffraction and single-crystal X-ray diffraction, respectively. Fixed cell geometry optimization calculations using density functional theory confirmed that the global optimum powder diffraction derived structure also matches an energy minimum structure. The energy calculations proved to be an effective tool in locating the positions of the H atoms reliably and verifying the salt configuration of the structure determined from powder data. Crystal packing analysis of these structures revealed that the loxapine succinate structure is based on chains of protonated loxapine molecules while the monohydrate contains dispersion stabilized centrosymmetric dimers. Incorporation of water molecules within the crystal lattice significantly alters the molecular packing and protonation state of the succinic acid.

Guest-Induced Isomerization of Net and Polymorphism in Trimesic Acid–Arylamine Complexes

Two molecular complexes of 1,3,5-benzenetricarboxylic acid (BTA) with 4,4′-methylenebis(2,6-dimethylaniline) (MBDA) and 2,6-dimethylaniline (DMA) led to the formation of two host guest systems. The MBDA species get trapped in hexagonal channels produced within the crystal lattice of the BTA. On the other hand, the DMA guest moieties are encapsulated into the channel formed by the brick wall network of BTA and water molecules. Isomerization of the (6,3) net, from hexagonal to brick wall, occurs due to the extra flexibility in the cluster of DMA guests which led to the additional hydrogen bonds with the host framework and incorporation of water molecules into the net. Each system contains two BTA species in the asymmetric unit with different ionic states, indicating that the proton transfer depends also upon the solid state environment. Crystallization of the BTA and MBDA mixture with different concentrations produces solvates of BTA–MBDA complex and MBDA crystallizes out in two forms depending upon the BTA...

Structural diversification of the coordination mode of divalent metals with 1,3-propanediaminetetraacetate (1,3-pdta): The missing crystal structure of the s-block metal complex [Sr 2(1,3-pdta)(H 2O) 6]·H 2O

This paper reports the synthesis and X-ray characteristics of the missing homonuclear s-block metal complex {[Sr 2(1,3-pdta)(H 2O) 6]·H 2O} n . In the title compound, the hexadentate 1,3-propanediaminetetraacetate (1,3-pdta) ligand joins to two Sr(II) centers via the diamine chain. Moreover, each Sr(II) is bridged through two carboxylate O atoms and a water molecule to two neighboring Sr(II) ions. The coordination sphere around each Sr(II) ion consists of one diamine nitrogen, four carboxylate oxygens and four water molecules. Comparison with the previously reported M(II)–1,3-pdta complexes reveals that increasing of the ion size results in the incorporation of water molecules into its first coordination sphere and consequent increase of the coordination number (C.N.) from six to seven or eight, while keeping the hexadentate coordination mode of the ligand. Further increase of the metal ion size leads to the loss of the chelating properties of the diamine and formation of a bis-tridentate complex. Associated with it is the change in the binding mode of the carboxylate groups. This forms the basis for classification of divalent metal 1,3-pdta complexes into five distinct structural classes. Additionally, in the present study X-ray powder diffraction and IR spectroscopy were used to distinguish the different structural types of M(II)–1,3-pdta complexes, including Ba[Ba(1,3-pdta)]·2H 2O which has been used for their preparation.

DL-Alaninium semi-oxalate monohydrate

The structure of the title compound, C(3)H(8)NO(2)(+)·C(2)HO(4)(-)·H(2)O, is formed by two chiral counterparts (L- and D-alaninium cations), semi-oxalate anions and water molecules, with a 1:1:1 cation-anion-water ratio. The structure is compared with that of the previously known anhydrous DL-alaninium semi-oxalate [Subha Nandhini, Krishnakumar & Natarajan (2001). Acta Cryst. E57, o666-o668] in order to investigate the role of water molecules in the crystal packing. The structure of the hydrate resembles that of anhydrous alaninium semi-oxalate, with the water molecule incorporated into the general three-dimensional network of hydrogen bonds where it forms four hydrogen bonds with neighbours disposed tetrahedrally about it. Although the main structural motifs in the hydrate and in the anhydrous form are topologically similar, the incorporation of water molecules in the network results in significant geometric distortion. There are several types of hydrogen bond in the crystal structure of the hydrate, two of which (O-H···O bonds between the semi-oxalate anions and O-H···O hydrogen bonds between water and alaninium cations) are very short. Such hydrogen bonds between semi-oxalate anions are also present in the anhydrous form of this compound. Short distances between semi-oxalate anions in neighbouring chains in the hydrate alternate with longer ones, whereas in the anhydrous structure they are equidistant. Despite the similarity of these compounds, dehydration of the hydrate on storage is not of a single-crystal to single-crystal type, but gives a polycrystalline pseudomorph, preserving the crystal habit. This transformation proceeds through the formation of an intermediate compound, presumably a hemihydrate.

Insight into Crystallization Mechanisms of Polymorphic Hydrate Systems

AbstractPolymorphic anhydrate systems have been well studied but until now little attention has been paid to polymorphic hydrate systems. The incorporation of water molecules can complicate the whole polymorphic system and thus impede the control of the crystallization process. In this work, nitrofurantoin monohydrate polymorphs which have the same chemical composition and molar ratio of water but different crystal packing arrangements, have been investigated. The metastable nitrofurantoin monohydrate was found to be difficult to crystallize, where both evaporative and cooling crystallization failed in its production. The possible phase conversion of the nitrofurantoin hydrate polymorphic system was also investigated in a liquid‐assisted ball milling process. High‐energy solids, e.g., amorphous and cocrystals, have often been created during high‐energy ball milling. Metastable nitrofurantoin monohydrate, however, was again not observed during the whole milling process, in contrast to another polymorphic hydrate system, namely niclosamide. During milling of niclosamide anhydrate in ethyl acetate‐water mixture the metastable niclosamide monohydrate was formed immediately upon milling (2 min). Under further milling, the metastable niclosamide hydrate started converting to the stable niclosamide hydrate (from 30 min onwards).

Development of N,N′-Diaromatic Diimidazolium Cations: Arene Interactions for Highly Organized Crystalline Materials

We applied concepts developed in the context of molecular recognition of aromatic rings in solution to design molecular tectons capable of generating molecular networks based on aromatic stacking in the crystalline phase. In this respect, N,N′-diaromatic diimidazolium cations are interesting tectons because they offer electron-rich (aromatic) and electron-poor (imidazolium) rings able to develop aromatic stacking interactions. Two positive charges and six acidic protons divergently oriented on the diimidazolium dication are involved in strong electrostatic charge−charge interactions and H-bonding with anions. Incorporation of aromatic rings modifies the rigidity of these dications. Depending on the flexibility of the molecules, incorporation of water molecules in the crystal lattice is possible, and channels are created in the solid network.

Influence of Superheated Water on the Hydrogen Bonding and Crystallography of Piperazine-Based (Co)polyamides

Here we demonstrate that superheated water is a solvent for polyamide 2,14 and piperazine-based copolyamides up to a piperazine content of 62 mol %. The incorporation of piperazine allows for a variation of the hydrogen bond density without altering the crystal structure (i.e., the piperazine units cocrystallize with the PA2,14 units (Hoffmann, S.; Vanhaecht, B.; Devroede, J.; Bras, W.; Koning, C. E.; Rastogi, S. Macromolecules 2005, 38, 1797-1803). It is shown that the crystallization of PA2,14 from superheated water greatly influences the crystal structure. Water molecules incorporated in the PA2,14 crystal lattice cause a slip on the hydrogen bonded planes, resulting in a coexistence of a triclinic and a monoclinic crystal structure. On heating above the Brill transition, the water molecules exit from the lattice, restoring the triclinic crystal structure. With increasing piperazine content, and hence decreasing hydrogen bond density, the dissolution temperature decreases. It is only possible to grow single crystals from superheated water up to a piperazine content of 62 mol %. For these single crystals, the incorporation of water molecules in the vicinity of the amide group is seen by the presence of COO- stretch vibrations with FTIR spectroscopy. These vibrations disappear on heating above the Brill transition temperature, and the water molecules leave the amide groups. For copolyamides with more than 62 mol % piperazine, no Brill transition is observed, no single crystals can be grown from water, and no water molecules are observed in the vicinity of the amide groups (Vinken, E.; Terry, A. E.; Hoffmann, S.; Vanhaecht, B.; Koning, C. E.; Rastogi, S. Macromolecules 2006, 39, 2546-2552). The high piperazine content (co)polyamides have fewer hydrogen bond donors and are therefore less likely to have interactions with the water molecules. This work demonstrates the relation among the Brill transition, the dissolution of polyamide in superheated water, and its influence on the hydrogen bonds and the amide groups.

Vibrational spectroscopic characterization of some environmentally important organoarsenicals — A guide for understanding the nature of their surface complexes

Organoarsenicals are found in the environment from the biomethylation of inorganic arsenic compounds and from anthropogenic sources. It is clear that organoarsenicals pose a health and an environmental risk due to their potential cycling to the most toxic forms of arsenic as a result of redox activity in soils and natural waters. The environmental fate of arsenic compounds depends to a large extent on the surface interactions with geosorbents, mainly minerals and organic matter. Hence, elucidating the nature of surface complexes is important in understanding binding mechanisms and thermodynamics. In this paper, we report the vibrational spectra of a number of organoarsenicals in the aqueous and solid phases using attenuated total internal reflectance Fourier transform infrared (ATR-FTIR), transmission FTIR, and Raman spectroscopies. Analysis of the aqueous phase spectra revealed that for completely deprotonated anions, increasing the organic substituents on the AsOx moiety results in increasing the frequency of v(AsOx), whereas the opposite trend is observed for completely protonated molecules. Analysis of solid phase spectra showed that incorporation of water molecules in the crystalline structure and extensive hydrogen bonding with neighboring molecules significantly affect As–O bond lengths and hence frequencies of v(AsOx). Results are discussed in the context of identifying geometry of organoarsenicals surface complexes in situ using the ATR-FTIR technique.Key words: ATR-FTIR, organoarsenicals; oxyanion adsorption, arsenate, in situ spectroscopy.

Coordination of trivalent lanthanum with polyethylene glycol in the presence of picrate anion: Spectroscopic and X-ray structural studies

The effect of polyethylene chain length on molecular structures of lanthanum–picrate–polyethylene glycol (PEG) complexes has been studied. The change in the ability of the inner coordination sphere to accommodate the largest size of La 3+ has been investigated in complexes with the ligands triethylene glycol (EO3), tetraethylene glycol (EO4), and pentaethylene glycol (EO5). The X-ray studies demonstrated that the complexes [La(Pic) 2(EO3) 2] +(Pic) − ( I and II), [La(Pic) 2(OH 2)(EO4)] +(Pic) −·H 2O ( III), and [La(Pic) 2(EO5)] +(Pic) − ( IV) crystallized in the monoclinic system in space groups P2 1/c ( I and IV), Pn ( II), and C2/c ( III). Compounds I and II are polymorphs. The La 3+ coordination with the PEG ligand in the presence of picrate anion (Pic) showed a coordination number of 10. The number of oxygen donor atoms dictated the geometry of the inner coordination sphere and the formation of additional inner-sphere ligands through the incorporation of water molecules, especially in III. The result with III is due to the availability of free space in the complex and to the lack of saturation of the inner coordination sphere. All crystals were further stabilized by π–π interactions stacking along the a-axis. No dissociation of La–O bonds in solution was observed in NMR studies conducted at different temperatures.

Partial volume and compressibility at infinite dilution of functionalized multilayer latex particles

A series of functionalized multilayer latex particles of P(butyl acrylate–methyl methacrylate–acrylic acid) was synthesized. The total acrylic acid concentration inside particles was varied from 0 to 25 wt.% and the number of particles in the system was held constant. The polymeric particles were studied by means of specific partial volume and specific partial compressibility at infinite dilution, which were calculated from density and sound speed measurements. From the behaviour of the partial properties at infinite dilution of the polar and non-polar groups of the polymer chain, it was concluded that the particle swells at low acrylic acids content due to the electrostatic repulsion between the carboxylic groups of the polymer chain. From 15 wt.% of acrylic acid up, the particle swells due to the electrostatic repulsion and to the incorporation of water molecules in the bounds of the particle layers. In this way, the hydration is non-homogeneous in the interior of each layer. These results are in agreement with the behaviour of the hydrodynamic radius determined by the quasi-elastic light scattering technique.

Nanoionics phenomenon in proton-conducting oxide: Effect of dispersion of nanosize platinum particles on electrical conduction properties

High-temperature proton conductors are oxides in which low-valence cations are doped as electron acceptors; the incorporation of water molecules into the oxides results in the formation of protonic defects that act as charge carriers. Since the protons thus formed are in equilibrium with other electronic defects, electrons and holes, the oxides possibly have different proton-conduction properties at and near boundaries when they are in contact with another phase. In this paper, we present our recent experimental observation of a marked change in the electrical properties of a proton conductor upon the dispersal of fine platinum particles in the oxide. First, the material shows extremely low electrical conductivity in comparison with the original proton-conducting perovskite. Second, there was a threshold amount of platinum at which such a drop in conductivity occurred. A percolation model is employed to explain these experimental results; the fine platinum particles dispersed in the proton-conducting oxide wears highly resistive skin that is formed due to shifts in defect equilibriums, which prevents ionic/electronic conduction. The experiments suggest that the ion-conducting properties of oxides can be varied by introducing interfaces at a certain density; nanoionics is a key to yielding enhanced and/or controlled ionic conduction in solids.

Structure, thermal and spectral study of 16α,17-epoxypregn-4-ene-3,11,20-trione monohydate

16α,17-epoxypregn-4-ene-3,11,20-trione is an important steroid intermediate in synthesis of many hormone pharmaceuticals, such as cortisone acetate and betamethason. It does not dissolve in water, but the single crystals grown from acetone with some water shows evident hydration behavior. The thermal analyses by DSC and TG-DTA and the IR spectra characterization of the anhydrous and hydrous crystals were performed and compared. The hydrate was also proved by IR spectral and thermal analyses. Single crystal structure of the hydrate indicates one water molecule per host molecule is included into the host lattice. The incorporation of water molecules does not change the crystal cell dimensions significantly, except for some increment of the cell along the axis b. In the crystal cell, two steroid molecules are linked through the water molecules as a bridge by forming two different hydrogen bonds. The incorporation of one water molecule makes some conformation changes of the molecules in the crystal unit cell.

Synthesis of Morphology Processable α-AlPO4Nanoparticles, Nanowires, and Multi-strand Nano-ropes

In this paper we present aluminum phosphate nanocrystals, prepared by a hydrothermal reaction, using amphiphilic triblock copolymer F127 [(EO) 1 0 6 (PO) 7 0 (EO) 1 0 6 ] as a morphology-directing template. By verifying the pH from 10 to 12, the morphology progression of AlPO 4 nanocrystals from nanoparticles to nanoparticle-aggregated nanowires, and finally to multi-strand nano-ropes, was successfully demonstrated. The most influential factors in the morphology process were the initial pH level, the participation of surfactant-template F127, and the change in pH during the reaction. We proposed a pH-dependent model to illustrate both the growth of AlPO 4 nanocrystals inside F127 amphiphilic domains and the chemical driving force that aggregated the nanoparticles into chain-shaped nanowires. The incorporation of water molecules as H-bonding linkers, to combine single nanowires into multi-strand nano-ropes, is also discussed in this model. Powder X-ray diffraction (XRD) patterns of the nanoparticle-aggregated nanowires and multi-strand nano-ropes were consistent with a mixed phase of berlinite and cristobalite structures, corresponding to the low-temperature form (a-form), while the AlPO 4 nanoparticles showed a pure berlinite phase only.