scholarly journals Conformal Self-Assembly of Nanospheres for Light-Enhanced Airtightness Monitoring and Room-Temperature Gas Sensing

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1829
Author(s):  
Qirui Liu ◽  
Yinlong Tan ◽  
Renyan Zhang ◽  
Yan Kang ◽  
Ganying Zeng ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Self Assembly ◽  
Room Temperature ◽  
Gas Sensing ◽  
Three Dimensional ◽  
Hydroxyl Groups ◽  
Universal Method ◽  
Feature Size ◽  
Simple Method ◽  
Hierarchical Architectures

The fabrication of conformal nanostructures on microarchitectures is of great significance for diverse applications. Here a facile and universal method was developed for conformal self-assembly of nanospheres on various substrates including convex bumps and concave holes. Hydrophobic microarchitectures could be transferred into superhydrophilic ones using plasma treatment due to the formation of numerous hydroxyl groups. Because of superhydrophilicity, the nanosphere suspension spread on the microarchitectures quickly and conformal self-assembly of nanospheres can be realized. Besides, the feature size of the conformal nanospheres on the substrates could be further regulated by plasma treatment. After transferring two-dimensional tungsten disulfide sheets onto the conformal nanospheres, the periodic nanosphere array was demonstrated to be able to enhance the light harvesting of WS2. Based on this, a light-enhanced room-temperature gas sensor with a fast recovery speed (<35 s) and low detecting limit (500 ppb) was achieved. Moreover, the WS2-covered nanospheres on the microarchitectures were very sensitive to the changes in air pressure due to the formation of suspended sheets on the convex bumps and concave holes. A sensitive photoelectronic pressure sensor that was capable of detecting the airtightness of vacuum devices was developed using the WS2-decorated hierarchical architectures. This work provides a simple method for the fabrication of conformal nanospheres on arbitrary substrates, which is promising for three-dimensional microfabrication of multifunctional hierarchical microarchitectures for diverse applications, such as biomimetic compound eyes, smart wetting surfaces and photonic crystals.

scholarly journals Three-dimensional platinum nanoparticle-based bridges for ammonia gas sensing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nishchay A. Isaac ◽  
Johannes Reiprich ◽  
Leslie Schlag ◽  
Pedro H. O. Moreira ◽  
Mostafa Baloochi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Response Times ◽  
High Surface ◽  
Three Dimensional ◽  
Performance Testing ◽  
Volume Ratio ◽  
Platinum Nanoparticle ◽  
Ammonia Gas ◽  
Lift Off

AbstractThis study demonstrates the fabrication of self-aligning three-dimensional (3D) platinum bridges for ammonia gas sensing using gas-phase electrodeposition. This deposition scheme can guide charged nanoparticles to predetermined locations on a surface with sub-micrometer resolution. A shutter-free deposition is possible, preventing the use of additional steps for lift-off and improving material yield. This method uses a spark discharge-based platinum nanoparticle source in combination with sequentially biased surface electrodes and charged photoresist patterns on a glass substrate. In this way, the parallel growth of multiple sensing nodes, in this case 3D self-aligning nanoparticle-based bridges, is accomplished. An array containing 360 locally grown bridges made out of 5 nm platinum nanoparticles is fabricated. The high surface-to-volume ratio of the 3D bridge morphology enables fast response and room temperature operated sensing capabilities. The bridges are preconditioned for ~ 24 h in nitrogen gas before being used for performance testing, ensuring drift-free sensor performance. In this study, platinum bridges are demonstrated to detect ammonia (NH3) with concentrations between 1400 and 100 ppm. The sensing mechanism, response times, cross-sensitivity, selectivity, and sensor stability are discussed. The device showed a sensor response of ~ 4% at 100 ppm NH3 with a 70% response time of 8 min at room temperature.

In Situ Visualization of Layer Transitions during Convective Self-Assembly in a Sessile Drop

2007 ◽  
Vol 31 ◽  
pp. 117-119
Author(s):  
Li Gao ◽  
Qing Feng Yan ◽  
C.C. Wong ◽  
Yet Ming Chiang
Keyword(s):  
Self Assembly ◽  
Sessile Drop ◽  
Three Dimensional ◽  
Colloidal Crystals ◽  
Layer Transition ◽  
Simple Method ◽  
Colloidal Spheres ◽  
In Situ Visualization ◽  
Set Up

Convective self-assembly of colloidal spheres provides a simple method for fabricating two and three dimensional colloidal crystals. In this work, we investigated the layer transitions phenomena during colloidal self-assembly in a sessile drop by using an in-situ videoscopic set-up. The effects of surface charge, colloidal concentration, and surfactant additions were examined. The results show that the chemical environment plays an important role in colloidal self-assembly. In the case of ordered growth, different layer transition phenomena were observed when the colloidal concentration is different.

Self-assembly of a Novel Three-dimensional Silver(I) Supramolecular Framework from Cationic Chains and Anionic Sheets

2010 ◽  
Vol 65 (2) ◽  
pp. 152-156
Author(s):  
Di Sun ◽  
Cheng-Feng Yang ◽  
Zhan-Hua Wei ◽  
Geng-Geng Luo ◽  
Na Zhang ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Hydrogen Bonds ◽  
Self Assembly ◽  
Room Temperature ◽  
Three Dimensional ◽  
Supramolecular Framework ◽  
Π Interactions ◽  
Π Stacking ◽  
Benzenedicarboxylic Acid

A new three-dimensional (3D) supramolecular framework, [Ag2(bipy)2(bdc)·4H2O]n 1, has been synthesized by the ultrasonic reaction of Ag2O, bipy and H2bdc (H2bdc = 1,4-benzenedicarboxylic acid; bipy = 4,4’-bipyridine) at room temperature. It exhibits a new 3D supramolecular framework which is built from cationic Ag-bipy chains and anionic bdc-H2O sheets through hydrogen bonds, π · · ·π stacking and C-H· · ·π interactions. Additionally, the photoluminescent and thermal properties of 1 were investigated.

Lyotropic Phase Behaviour and Structural Parameters of Monosaccharide and Disaccharide Guerbet Branched-Chain β-D-Glycosides

2014 ◽  
Vol 895 ◽  
pp. 111-115 ◽  
Author(s):  
Hairul A.A. Hamid ◽  
Rauzah Hashim ◽  
John M. Seddon ◽  
Nicholas J. Brooks
Keyword(s):  
Self Assembly ◽  
Room Temperature ◽  
Structural Parameters ◽  
Phase Behaviour ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Branched Chain ◽  
Optical Polarizing Microscopy ◽  
Water Contents

The phase behaviour and self-assembly structural parameters of a pair of monosaccharide and disaccharide Guerbet branched-chain β-D-glycosides, namely 2-octyldodecyl β-D-glucoside (β-Glc-C12C8) and 2-octyldodecyl β-D-maltoside (β-Mal-C12C8), have been studied by means of optical polarizing microscopy (OPM) and small-angle X-ray diffraction at room temperature (25°C). These compounds are sugar-based glycolipid surfactants having a total chain length of C20, and differ based on the increasing number of hydroxyl groups of the sugar headgroup (glucose and maltose). The repeat spacings obtained by X-ray diffraction as a function of water content have been used to determine the limiting hydration for the two glycosides. At room temperature, β-Glc-C12C8 and β-Mal-C12C8 have limiting hydrations of 22 wt% and 25 wt%, corresponding to 8 10 and 10 12 water molecules per glycoside, respectively. At all water contents between 5 and 29 wt % water, these compounds adopt inverse hexagonal (HII) or fluid lamellar (Lα) phases. The structural parameters of these phases have been determined from the diffraction data, from the X-ray repeat spacings, densities and concentration of the glycosides.

3D Photonic Structures by Sol-Gel Imprint Lithography

2007 ◽  
Vol 1002 ◽  
Author(s):  
Marc Verschuuren ◽  
Hans Van Sprang
Keyword(s):  
Self Assembly ◽  
Room Temperature ◽  
Sol Gel ◽  
Three Dimensional ◽  
Imprint Lithography ◽  
Replication Process ◽  
Simple Process ◽  
Excellent Quality ◽  
Photonic Structures ◽  
Silica Material

ABSTRACTWe present a new and relatively simple process to manufacture three-dimensional sub-micron structures over square centimeter areas using a soft stamp imprinting process. The room-temperature replication process shows excellent quality in transferring features directly into inorganic silica material with pattern distortion smaller than 0.03% over an area of 15×15mm2. Using a self assembly planarization method the imprinting process can be repeated to form three-dimensional structures. As a demonstration, a multilayer stack of four crossed gratings is shown.

Supramolecular self-assembly of three-dimensional polyaniline and polypyrrole crystals

2014 ◽  
Vol 50 (84) ◽  
pp. 12757-12760 ◽  
Author(s):  
Yulun Tao ◽  
Juchuan Li ◽  
Anjian Xie ◽  
Shikuo Li ◽  
Ping Chen ◽  
...  
Keyword(s):  
Self Assembly ◽  
Room Temperature ◽  
Conductive Polymer ◽  
Three Dimensional ◽  
Polymer Crystals ◽  
Solvent Environment

Supramolecular self-assembly of 3D conductive polymer crystals in a suitable solvent environment at room temperature.

Scanning Tunneling Microscopy Study of α,ω-Dihexylsexithiophene Adlayers on Au(111): A Chiral Separation Induced by a Surface

2012 ◽  
Vol 18 (4) ◽  
pp. 885-891 ◽  
Author(s):  
Yonghai Song ◽  
Yu Wang ◽  
Lingli Wan ◽  
Shuhong Ye ◽  
Haoqing Hou ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Self Assembly ◽  
Room Temperature ◽  
Three Dimensional ◽  
Microscopy Study ◽  
Molecular Structures ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Left Handed ◽  
Bulk Structure

AbstractThe self-assembly of α,ω-dihexylsexithiophene molecules on an Au(111) surface was examined by using scanning tunneling microscopy at room temperature, revealing the internal molecular structures of the sexithiophene backbones and the hexyl side chains. The α,ω-dihexylsexithiophene formed a large and well-ordered monolayer in which the molecule lay flatly on the Au(111) surface and was separated into two chiral domains. A detailed observation reveals that the admolecules were packed in one lamellae with their molecular axis aligned along the main axis of the Au(111) substrate with their hexyl chains deviated from ⟨110⟩ direction of the Au(111) substrate by 12 ± 0.5°. In contrast to the behavior in the three-dimensional bulk structure, flat-lying adsorption introduced molecular chirality: right- and left-handed molecules separate into domains of two different orientations, which are mirror symmetric with respect to the ⟨121⟩ direction of the Au(111) substrate. Details of the adlayer structure and the chiral self-assembly were discussed here.

Template-Free Synthesis and Properties of Polyaniline Nanostructures Doped with Different Oxidants

2011 ◽  
Vol 688 ◽  
pp. 334-338 ◽  
Author(s):  
He Yang ◽  
Yun Ze Long ◽  
Hang Jun Ding
Keyword(s):  
Self Assembly ◽  
Room Temperature ◽  
Three Dimensional ◽  
Ammonium Persulfate ◽  
Molar Ratio ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Assembly Method ◽  
Temperature Dependence Of Conductivity ◽  
Template Free

In this work, we report on conducting polyaniline (PANI) nanostructures synthesized by a simplified template-free self-assembly method, which are doped with different oxidants such as ammonium persulfate (APS), FeCl3, Fe(NO3)3, and Fe2(SO4)3. It is found that the morphologies of the as-prepared PANI nanowires are dependent on the oxidant and the molar ratio of aniline to oxidant. The PANI nanostructures are semiconducting with room-temperature conductivity ranging from 10-2to 100S/cm, and the temperature dependence of conductivity follows three-dimensional Mott variable range hopping (3D Mott-VRH) model. In addition, the PANI pellets exhibit hydrophilic behavior.

Periodically ordered nanohetero inorganic structures of nanoparticles, nanorods and layers in a matrix from self-assembled block copolymers

2014 ◽  
Vol 1706 ◽  
Author(s):  
Hiroaki Wakayama ◽  
Hirotaka Yonekura ◽  
Yasuaki Kawai
Keyword(s):  
Block Copolymers ◽  
Self Assembly ◽  
Three Dimensional ◽  
Functional Materials ◽  
Domain Size ◽  
Great Promise ◽  
Layer By Layer ◽  
Simple Method ◽  
Self Assembled ◽  
Size And Morphology

ABSTRACTPeriodically ordered nanohetero inorganic structures offer great promise due to their unique electric, ionic, magnetic, and photonic properties. Many studies have focused on the formation of periodically ordered nano-hetero inorganic structures through layer-by-layer adsorption, sputtering, and self-assembly methods. However, the construction of three-dimensional periodically ordered nanohetero inorganic structures with desired sizes and morphologies remains a great challenge. We present a simple method for producing three-dimensional periodically ordered inorganic nanoheterostructures with controlled shape and size by replicating self-assembled block copolymers (BCPs) containing precursors of metals and metal oxides. Precursors were dissolved with BCPs in a solvent. Upon evaporation of the solvent, each precursor was selectively introduced into a separate polymer block. Application of an external magnetic field (10 T) to the BCP-precursor composites resulted in a phase transition of from spheres to hexagonal cylinders. Subsequent pyrolytic removal of the BCPs produced periodically ordered nanoheterostructures that were structural replicates of the precursor–BCP composites. Self-assembled nano-hetero inorganic structures of nanoparticles, nanorods and layers in a matrix were produced. The morphology and domain size can be tailored by controlling the molecular weight and relative block length of block copolymers. The controlled size and morphology of the inorganic nanoheterostructures demonstrate the method’s utility for producing highly functional materials.

Sign in / Sign up

Export Citation Format

Share Document