Periodic Surface-Ring Pattern Formation for Hydroxyapatite Thin Films Formed by Biomineralization-Inspired Processes

Han, Ya Fang; Nishimura, Tatsuya; Iimura, Misato; Sakamoto, Takeshi; Ohtsuki, Chikara; Kato, Takashi

doi:10.1021/acs.langmuir.7b02126

Cited by 6 publications

(14 citation statements)

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“…Even hybrid inorganic compounds with polymers can form periodic bands. Kato et al 41 recently synthesized organic-inorganic hybrid compounds of hydroxyapatite (HAP)/poly(2-hydroxyethyl methacrylate) spin-cast as thin films on treated glass slides, and they proved formation of periodic rings with band spacing of ~3 μm. For long-chain polymers with chain folding back and forth in the lamellae, many investigators intuitively attributed the formation of periodic rings in polymers to lamellae being helix-twisted into a continuous screw-like thread by the "surface stresses" due to chain folding [42][43][44] .…”

Section: Resultsmentioning

confidence: 99%

Periodic Fractal-Growth Branching to Nano-Structured Grating Aggregation in Phthalic Acid

Chen

Woo

2020

Sci Rep

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Small-molecule phthalic acid (PA), confined in micrometer thin films, was crystallized in the presence of strongly interacting tannic acid (TA) to investigate crystal assembly and correlation between banded patterns and branching structures. Several compositions of the mixture of ethanol/water solutions and evaporation temperatures were also manipulated to investigate the kinetic effects on the morphology of PA crystals. With increasing evaporation rate, the morphology of PA crystals systematically changes from circular-banded spherulites to highly ordered grating-banded patterns. A unique periodic fractalbranch pattern with contrasted birefringent bands exists at intermediate evaporation rate, and this unique grating architecture has never been found in other banded crystals. Crystal assembly of these three periodic morphologies was analyzed by utilizing atomic-force microscopy (AFM) and scanning electron microscopy (SEM) to reveal the mechanisms of formation of hierarchical structures of PA. The detailed growth mechanisms of the novel fractal-branching assembly into circular-or grating-banded patterns are analyzed in this work.Cooling of a matter in liquid state causes it to crystallize into either 2D or 3D ordered states. The crystallization process may occur in sequential steps to gradually increase the degree of order while in the meantime the hierarchical aggregation structures may diversify in patterns and vary significantly in increasingly higher-order morphologies. Crystallization of atoms or molecular compounds into ordered states has been a complex yet fascinating phenomenon that has attracted extensive scientific studies from classical to modern times, to cite just a few recent examples 1-3 . Self-assembly of organic or inorganic compounds, of either small-molecules or polymers, has been interesting and intriguing, yet complex issues, in soft matters either synthetic or natural. Fractal patterns are widely seen in hierarchical structural assemblies in natural materials. Khire and Yadavalli, et al. 4 by using high-resolution atomic-force microscopy (AFM), investigated the fractal self-assembly of silk protein sericin [a protein by Bombyx mori (silkworms) in producing silk], and observed the fractal structure of the silk protein's self-assembly, where they proposed that the protein globules may be thought to act as seeds for the subsequent attachment of protein molecules and the formation of the fractal architectures. Guo et al. 5 studied the relationship between the fractal-ladder viscoelastic behavior of bio-fibers with fractal ladder hyper-cell structures. Snowflakes or aggregates of self-similar snow/ice single crystals are well known to be an excellent example of fractal patterns in nature. Yang, et al. 6 proposed the fractal growth kinematics of snow-flakes with many self-similar multilevel small structures. Crystalline morphology is governed by the cooperation of the driving force of crystallization and the transport of atom, ions, molecules, and heat. 7 When the growth condition is relatively...

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Section: Resultsmentioning

confidence: 99%

Periodic Fractal-Growth Branching to Nano-Structured Grating Aggregation in Phthalic Acid

Chen

Woo

2020

Sci Rep

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“…The nanocrystalline features of the OCP crystals formed in the hybrid thin films enabled the rapid, topotactic transformation to occur in the aqueous solution process. 21,23,51 The inorganic amounts within the OCP and HAP hybrid thin films were estimated using thermogravimetric (TG) measurements under a flow of N 2 . Weight losses that were attributed to the removal of water molecules within the PVA templates and the decomposition of PVA were clearly observed in TG curves (Figure 7).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Tuning the c-Axis Orientation of Calcium Phosphate Hybrid Thin Films Using Polymer Templates

et al. 2019

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The orientation of the c-axis in octacalcium phosphate (OCP) nanocrystals that were incorporated into hybrid thin films was successfully tuned using poly(vinyl alcohol) (PVA) thin-film templates of varying thicknesses. This approach was inspired by biomineralization. Thicker PVA templates enhanced the c-axis orientation of the OCP crystals perpendicular to the substrate. Using this approach with a 900 nm thick PVA template, OCP/PVA hybrid thin films (1.8 μm thick) with a c-axis orientation perpendicular to the substrate were formed. Hydroxyapatite (HAP) hybrid thin films that also exhibited a perpendicular c-axis orientation were obtained through the topotactic transformation of the OCP/PVA hybrid thin films in aqueous solution. The thickness change of the polymer templates had a significant effect on the structure of the OCP nanocrystals in the hybrid thin films. The structural control of the OCP hybrid thin films that were formed through the biomineralization-inspired approach allowed the formation of HAP hybrid thin films with controlled structures.

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“…Our biomineralization-inspired approaches can be applied for the formation of various organic/inorganic composite materials. 12,62,63 For example, calcium phosphate-based composite materials that have a potential for applications in a wide range of fields such as biomedical may be developed. 12,24,64 The present study promises that mimicking biomimetic structures could lead to the development of hard, strong, and transparent materials from abundant natural resources.…”

Section: Discussionmentioning

confidence: 99%

Bioinspired Environmentally Friendly Amorphous CaCO₃-Based Transparent Composites Comprising Cellulose Nanofibers

et al. 2018

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Amorphous calcium carbonate (ACC) stabilized by acidic macromolecules is a useful material for the development of environmentally friendly composites. In this study, we synthesized transparent and mechanically tough ACC-based composite materials by the incorporation of water-dispersible cellulose derivatives, namely, carboxymethyl cellulose (CMC) and surface-modified crystalline cellulose nanofibers (CNFs). A solution mixing method used in the present work proved to be a powerful and efficient method for the production of mechanically tough and environmentally friendly materials. Molecular-scale interactions between carboxyl groups and Ca 2+ ions induce homogeneous dispersion of CNFs in the composites, and this gives composite films with high transparency and high mechanical properties. The composite films of CMC, CNFs, and ACC at the mixture ratios of 40, 40, and 20 wt %, showed high mechanical properties of 15.8 ± 0.93 GPa for the Young’s modulus and 268 ± 20 MPa for the tensile strength. These designed materials that are based on ACC may open up new opportunities in many fields in applications that require the use of environmentally friendly, biodegradable, mechanically tough, and transparent composite materials.

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Periodic Surface-Ring Pattern Formation for Hydroxyapatite Thin Films Formed by Biomineralization-Inspired Processes

Cited by 6 publications

References 61 publications

Periodic Fractal-Growth Branching to Nano-Structured Grating Aggregation in Phthalic Acid

Periodic Fractal-Growth Branching to Nano-Structured Grating Aggregation in Phthalic Acid

Tuning the c-Axis Orientation of Calcium Phosphate Hybrid Thin Films Using Polymer Templates

Bioinspired Environmentally Friendly Amorphous CaCO₃-Based Transparent Composites Comprising Cellulose Nanofibers

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Periodic Surface-Ring Pattern Formation for Hydroxyapatite Thin Films Formed by Biomineralization-Inspired Processes

Cited by 6 publications

References 61 publications

Periodic Fractal-Growth Branching to Nano-Structured Grating Aggregation in Phthalic Acid

Periodic Fractal-Growth Branching to Nano-Structured Grating Aggregation in Phthalic Acid

Tuning the c-Axis Orientation of Calcium Phosphate Hybrid Thin Films Using Polymer Templates

Bioinspired Environmentally Friendly Amorphous CaCO3-Based Transparent Composites Comprising Cellulose Nanofibers

Contact Info

Product

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About

Bioinspired Environmentally Friendly Amorphous CaCO₃-Based Transparent Composites Comprising Cellulose Nanofibers