scholarly journals Concentration-driven phase transition and self-assembly in drying droplets of diluting whole blood

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Anusuya Pal ◽  
Amalesh Gope ◽  
John D. Obayemi ◽  
Germano S. Iannacchione
Keyword(s):  
Phase Transition ◽  
Self Assembly ◽  
Whole Blood ◽  
Morphological Analysis ◽  
Hierarchical Structures ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Colloidal Systems ◽  
Functional Complexity ◽  
Sharp Phase Transition

Abstract Multi-colloidal systems exhibit a variety of structural and functional complexity owing to their ability to interact amongst different components into self-assembled structures. This paper presents experimental confirmations that reveal an interesting sharp phase transition during the drying state and in the dried film as a function of diluting concentrations ranging from 100% (undiluted whole blood) to 12.5% (diluted concentrations). An additional complementary contact angle measurement exhibits a monotonic decrease with a peak as a function of drying. This peak is related to a change in visco-elasticity that decreases with dilution, and disappears at the dilution concentration for the observed phase transition equivalent to 62% (v/v). This unique behavior is clearly commensurate with the optical image statistics and morphological analysis; and it is driven by the decrease in the interactions between various components within this bio-colloid. The implications of these phenomenal systems may address many open-ended questions of complex hierarchical structures.

Contact Angle of Nepenthes alata Slippery Zone: Results from Measurement and Model Analysis

2021 ◽  
pp. 1-7
Author(s):  
Lixin Wang ◽  
Pan Pan ◽  
Shixing Yan ◽  
Shiyun Dong
Keyword(s):  
Contact Angle ◽  
Hierarchical Structures ◽  
Model Analysis ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Structure Characteristic ◽  
Baxter Equation ◽  
Measured Contact Angle ◽  
The Relationship ◽  
Contact Angle Analysis

The slippery zone of Nepenthes alata depends on its highly evolved morphology and structure to show remarkable superhydrophobicity, which has gradually become a biomimetic prototype for developing superhydrophobic materials. However, the mechanism governing this phenomenon has not been fully revealed through model analysis. In this paper, the superhydrophobicity of slippery zone is studied by contact angle measurement, morphology/structure examination and model analysis. The slippery zone causes ultrapure water droplet to produce a considerably high contact angle (155.11–158.30°), and has a micro-nano scale hierarchical structures consisting of lunate cells and wax coverings. According to the Cassie-Baxter equation and a self-defined infiltration coefficient, a model was established to analyze the effect of structure characteristic on the contact angle. Analysis result showed that the calculated contact angle (154.67–159.49°) was highly consistent with the measured contact angle, indicating that the established model can quantitatively characterize the relationship between the contact angle and the structure characteristic. Our study provides some evidences to further reveal the superhydrophobic mechanism of Nepenthes alata slippery zone, as well as inspires the biomimetic development of superhydrophobic surfaces.

SYNTHESIS AND CHARACTERIZATION OF SUPERHYDROPHOBIC ZnO HIERARCHICAL STRUCTURES

NANO ◽  
2011 ◽  
Vol 06 (03) ◽  
pp. 265-269 ◽  
Author(s):  
QUNBING ZHANG ◽  
SHIHE CAO ◽  
JUN WANG
Keyword(s):  
Contact Angle ◽  
Hydrothermal Process ◽  
Hierarchical Structures ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Zno Films ◽  
Water Contact ◽  
Simple Method ◽  
Microscopy Images

ZnO films with well-aligned hierarchical structures have been successfully synthesized at moderate temperatures using a simple catalyst-free hydrothermal process. The synthesized ZnO films are found to be single-phase, with a hexagonal wurtzite-type structure. Scanning electron microscopy images show that the well-aligned hierarchical structures are assembled with interlaced parallel sheets grown on the (400) silica surface. The water contact angle measurement indicates that the water on the films has a contact angle of about 156.3°. This clearly demonstrates that the ZnO films synthesized by this simple method have superhydrophobic properties and may be important for applications in self-cleaning surfaces, biology, and so on.

Fabrication of Composite Carbon Nanotubes With Different Oxidation Levels by a Self-Assembly Surface Modification

2006 ◽  
Author(s):  
Chien-Te Hsieh ◽  
Kuen-Song Lin ◽  
Shih Hung Chan ◽  
Ay Su
Keyword(s):  
Carbon Nanotubes ◽  
Metal Oxide ◽  
Metal Ions ◽  
Self Assembly ◽  
Carbon Composite ◽  
Atomic Ratio ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Hydroxyl Group ◽  
Surface Oxides

An efficient technique to fabricate metal-oxide/carbon composite nanotubes has been developed through a self-assembly processing that includes implantation of acidic groups and interaction between surface oxides and metal ions or hydration molecules. To functionalize carbon nanotubes, gaseous oxidation at 300 °C was firstly employed to build functional oxygen groups including carboxyl, carbonyl and hydroxyl group, on the ends or sidewalls of the nanotubes. It revealed that the oxidized nanotubes express a slight improvement of surface hydrophilicity, which was demonstrated by contact angle measurement. X-ray photoelectron spectroscope investigation indicated that the ratio of attached metal-oxide onto the oxidized nanotubes gradually increases with oxidation level, i.e., surface O/C atomic ratio. This evidence reflected that the surface oxides act as an adsorption center that strongly interacts with metal ions or hydration molecules in aqueous phase. Applying this method, SnO2, RuO2, NiO and PtRu nanoparticles having an average size of 5 nm were assembled on the oxidized carbon nanotubes.

scholarly journals A metallic anti-biofouling surface with a hierarchical topography containing nanostructures on curved micro-riblets

2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Taekyung Kim ◽  
Sunmok Kwon ◽  
Jeehyeon Lee ◽  
Joon Sang Lee ◽  
Shinill Kang
Keyword(s):  
Contact Angle ◽  
Hierarchical Structures ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Bacterial Attachment ◽  
Resistance Testing ◽  
Metallic Surface ◽  
Metallic Surfaces ◽  
Hydration Layer ◽  
Surface Finishes

AbstractMetallic surface finishes have been used in the anti-biofouling, but it is very difficult to produce surfaces with hierarchically ordered structures. In the present study, anti-biofouling metallic surfaces with nanostructures superimposed on curved micro-riblets were produced via top-down fabrication. According to the attachment theory, these surfaces feature few attachment points for organisms, the nanostructures prevent the attachment of bacteria and algal zoospores, while the micro-riblets prohibit the settlement of macrofoulers. Anodic oxidation was performed to induce superhydrophilicity. It forms a hydration layer on the surface, which physically blocks foulant adsorption along with the anti-biofouling topography. We characterized the surfaces via scanning electron and atomic force microscopy, contact-angle measurement, and wear-resistance testing. The contact angle of the hierarchical structures was less than 1°. Laboratory settlement assays verified that bacterial attachment was dramatically reduced by the nanostructures and/or the hydration layer, attributable to superhydrophilicity. The micro-riblets prohibited the settlement of macrofoulers. Over 77 days of static immersion in the sea during summer, the metallic surface showed significantly less biofouling compared to a surface painted with an anticorrosive coating.

The Temperature-Sensitive Behaviors of SMPU/PNIPAM Semi-IPN Films

2013 ◽  
Vol 712-715 ◽  
pp. 373-377
Author(s):  
Zheng Xia Xu ◽  
Zheng Wei Dai ◽  
Yuan Xue
Keyword(s):  
Phase Transition ◽  
Polymer Network ◽  
Water Vapor Permeability ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Interpenetrating Polymer Network ◽  
Vapor Permeability ◽  
Temperature Sensitive ◽  
Water Contact ◽  
Different Temperatures

A semi-interpenetrating polymer network was fabricated from SMPU (Shape-Memory Polyureathan and PNIPAM (poly (N-isopropylacrylamide)) with the method of in-situ crosslinking polymerization. The temperature-sensitivity of the semi-IPN films was investigated and discussed. The morphology was achieved by extracting the SMPU phase. The influence of PNIPAM phase to the phase transition behavior of SMPU was studied with DSC, the results of which showing that the phase transition temperature is increased by PNIPAM. The introduction of PNIPAM also endows the semi-IPN films with a temperature-sensitive surface hydrophilicity, which was proved by water contact angle measurement at different temperatures. Finally, the water vapor permeability evaluation reveals the temperature-sensitive transportation property of the semi-IPN films, which is formed by the swelling and shrinking of PNIPAM phase according to the environmental temperature. These results shows that the semi-IPN material is a good candidate for the fabrication of intelligent breathable garments.

scholarly journals Nanogap Capacitors for Label Free DNA Analysis

2002 ◽  
Vol 729 ◽  
Author(s):  
Joon Sung Lee ◽  
Yang-Kyu Choi ◽  
Michael Pio ◽  
Jeonggi Seo ◽  
Luke P. Lee
Keyword(s):  
Self Assembly ◽  
Dna Hybridization ◽  
Dna Analysis ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Detection Sensitivity ◽  
Label Free ◽  
Double Stranded Dna ◽  
The Difference ◽  
Dielectrical Properties

AbstractNanogap capacitors are fabricated for DNA hybridization detection. Without labeling, the nanogap capacitors on a chip can function as DNA microarray sensors. The difference in dielectric properties between single-stranded DNA and double-stranded DNA permits use of capacitance measurements to detect hybridization. To obtain high detection sensitivity, a 50 nm gap capacitor was fabricated using a Si-nanotechnology. To ensure proper measurement of DNA's dielectrical properties, the probe ssDNA was first immobilized onto the electrode surface using self-assembly monolayers and allowed to hybridize with the target ssDNA. The capacitance changes were measured for 35-mer homonucleotides. The self-assembly monolayer and DNA immobilization events were verified independently by contact angle measurement and FTIR. Capacitance values are measured at frequencies ranging from 75 kHz to 5 MHz, using 0 VDC bias and 25 mVAC signals. Approximately 9% change in capacitance was observed after DNA hybridization at 75 kHz.

Fabrication of Transparent Hydrophilic Nanosized TiO2 Films via Layer-by-Layer Self-Assembly

2016 ◽  
Vol 852 ◽  
pp. 1075-1079
Author(s):  
Zhi Yong Zeng ◽  
Ying Shi ◽  
Su Jun Yuan ◽  
Jian Jun Xie
Keyword(s):  
Contact Angle ◽  
Self Assembly ◽  
Hydrothermal Process ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Layer By Layer ◽  
Water Contact ◽  
Assembly Method ◽  
Oppositely Charged ◽  
Positively Charged

The transparent nanosized TiO2 film was fabricated by a layer-by-layer assembly method starting from the highly dispersed anatase oppositely charged TiO2 nanoparticles without using anypoly electrolytes. The positively charged TiO2 nanoparticles (ca.7 nm) and negatively charged TiO2 nanoparticles (ca.7 nm) were synthesized by a subsequently hydrothermal process. Field-emission scanning electron microscopy, UV-vis transmittance spectra and Contact angle measurement were employed to characterize TiO2films.By the treatment of 500°C for 2hrs, the nanostructured TiO2 film showed a water contact angle of below 10°andthe relative transmittance to quartz glass of over 90%.

Biomimetic materials: An introduction

1992 ◽  
Vol 50 (2) ◽  
pp. 1020-1021 ◽  
Author(s):  
M. Sarikaya ◽  
J. T. Staley ◽  
I. A. Aksay
Keyword(s):  
Self Assembly ◽  
Structural Control ◽  
Hierarchical Structures ◽  
Ceramic Composites ◽  
Advanced Materials ◽  
Length Scale ◽  
Spider Webs ◽  
Biomimetic Materials ◽  
Synthetic Materials ◽  
All Ceramic

Biomimetics is an area of research in which the analysis of structures and functions of natural materials provide a source of inspiration for design and processing concepts for novel synthetic materials. Through biomimetics, it may be possible to establish structural control on a continuous length scale, resulting in superior structures able to withstand the requirements placed upon advanced materials. It is well recognized that biological systems efficiently produce complex and hierarchical structures on the molecular, micrometer, and macro scales with unique properties, and with greater structural control than is possible with synthetic materials. The dynamism of these systems allows the collection and transport of constituents; the nucleation, configuration, and growth of new structures by self-assembly; and the repair and replacement of old and damaged components. These materials include all-organic components such as spider webs and insect cuticles (Fig. 1); inorganic-organic composites, such as seashells (Fig. 2) and bones; all-ceramic composites, such as sea urchin teeth, spines, and other skeletal units (Fig. 3); and inorganic ultrafine magnetic and semiconducting particles produced by bacteria and algae, respectively (Fig. 4).

Reversible microscale assembly of nanoparticles driven by the phase transition of a thermotropic liquid crystal

2017 ◽  
Author(s):  
Niamh Mac Fhionnlaoich ◽  
Stephen Schrettl ◽  
Nicholas B. Tito ◽  
Ye Yang ◽  
Malavika Nair ◽  
...  
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Self Assembly ◽  
Nematic Phase ◽  
Hierarchical Control ◽  
Building Blocks ◽  
Model System ◽  
Microscopic Level ◽  
Reversible Process ◽  
Thermotropic Liquid Crystal

The arrangement of nanoscale building blocks into patterns with microscale periodicity is challenging to achieve via self-assembly processes. Here, we report on the phase transition-driven collective assembly of gold nanoparticles in a thermotropic liquid crystal. A temperature-induced transition from the isotropic to the nematic phase leads to the assembly of individual nanometre-sized particles into arrays of micrometre-sized aggregates, whose size and characteristic spacing can be tuned by varying the cooling rate. This fully reversible process offers hierarchical control over structural order on the molecular, nanoscopic, and microscopic level and is an interesting model system for the programmable patterning of nanocomposites with access to micrometre-sized periodicities.

scholarly journals Metal Oxide-Related Dendritic Structures: Self-Assembly and Applications for Sensor, Catalysis, Energy Conversion and Beyond

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1686
Author(s):  
Ruohong Sui ◽  
Paul A. Charpentier ◽  
Robert A. Marriott
Keyword(s):  
Metal Oxide ◽  
Energy Conversion ◽  
Self Assembly ◽  
Hierarchical Structures ◽  
The Self ◽  
Assembly Process ◽  
Electronic Noses ◽  
Dendritic Nanostructures ◽  
Energy Conversion And Storage ◽  
The Aesthetic

In the past two decades, we have learned a great deal about self-assembly of dendritic metal oxide structures, partially inspired by the nanostructures mimicking the aesthetic hierarchical structures of ferns and corals. The self-assembly process involves either anisotropic polycondensation or molecular recognition mechanisms. The major driving force for research in this field is due to the wide variety of applications in addition to the unique structures and properties of these dendritic nanostructures. Our purpose of this minireview is twofold: (1) to showcase what we have learned so far about how the self-assembly process occurs; and (2) to encourage people to use this type of material for drug delivery, renewable energy conversion and storage, biomaterials, and electronic noses.

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