scholarly journals Breath figure templated self-assembly of surface-acylated cellulose nanowhiskers confined as honeycomb films

2021 ◽  
Author(s):  
Huan Liu ◽  
Bo Pang ◽  
Kai Zhang
Keyword(s):  
Relative Humidity ◽  
Self Assembly ◽  
Three Dimensional ◽  
Planar Geometry ◽  
Cellulose Nanowhiskers ◽  
Water Droplets ◽  
Porous Films ◽  
Structural Colors ◽  
Breath Figure ◽  
High Concentrations

Abstract The self-assembly of cellulose nanowhiskers (CNWs) in confined geometries provides a powerful method for the fabrication of novel structures. Herein, ordered honeycomb microporous films were first prepared with surface-acylated CNWs (CNWs-SU) through the breath figure method. Resulting films showed highly porous order over large regions and the iridescent color was only displayed by their rims, which is different from traditional dish-cast CNW films showing the iridescent color over the whole area. This is mainly due to the condensation of water droplets forming three-dimensional (3D) geometry, which forced CNWs-SU to self-assemble into cholesteric architectures in confined geometry and resulted in the iridescent color of the rims after drying. The mechanism was further studied by investigating the critical influencing factors, primarily the concentration of CNW-SU suspensions, the relative humidity of the atmosphere and the surface-attached moieties. In particular, CNW-SU suspensions with a concentration of 3 mg/mL at the relative humidity of 75% preferentially formed honeycomb films with uniform pores. Too low or too high concentrations of CNW-SU suspensions or relative humidity are not preferable for uniform porous films. CNWs-SU with further immobilized octadecane or fluoroalkyl groups on their surface strongly affected the formation of uniform porous films because of higher hydrophobicity and accompanying inhomogeneous condensation of water droplets. This work provides a novel method to study the interactions of CNWs beyond the planar geometry and the formation of uniform porous films solely with CNWs with structural colors for diverse potential applications.

scholarly journals Breath figure templated self-assembly of surface-acylated cellulose nanowhiskers confined as honeycomb films

Cellulose ◽  
2021 ◽  
Author(s):  
Huan Liu ◽  
Bo Pang ◽  
Kai Zhang
Keyword(s):  
Relative Humidity ◽  
Self Assembly ◽  
Three Dimensional ◽  
Planar Geometry ◽  
Cellulose Nanowhiskers ◽  
Water Droplets ◽  
Porous Films ◽  
Structural Colors ◽  
Breath Figure ◽  
High Concentrations

AbstractThe self-assembly of cellulose nanowhiskers (CNWs) in confined geometries provides a powerful method for the fabrication of novel structures. Herein, ordered honeycomb microporous films were first prepared with surface-acylated CNWs (CNWs-SU) through the breath figure method. Resulting films showed highly porous order over large regions and the iridescent color was only displayed by their rims, which is different from traditional dish-cast CNW films showing the iridescent color over the whole area. This is mainly due to the condensation of water droplets forming three-dimensional (3D) geometry, which forced CNWs-SU to self-assemble into cholesteric architectures in confined geometry and resulted in the iridescent color of the rims after drying. The mechanism was further studied by investigating the critical influencing factors, primarily the concentration of CNW-SU suspensions, the relative humidity of the atmosphere and the surface-attached moieties. In particular, CNW-SU suspensions with a concentration of 3 mg/mL at the relative humidity of 75% preferentially formed honeycomb films with uniform pores. Too low or too high concentrations of CNW-SU suspensions or relative humidity are not preferable for uniform porous films. CNWs-SU with further immobilized octadecane or fluoroalkyl groups on their surface strongly affected the formation of uniform porous films because of higher hydrophobicity and accompanying inhomogeneous condensation of water droplets. This work provides a novel method to study the interactions of CNWs beyond the planar geometry and the formation of uniform porous films solely with CNWs with structural colors open up interesting possibilities for broad application in photonic nanomaterials. Graphic abstract

scholarly journals Atmospheric modelling of grass pollen rupturing mechanisms for thunderstorm asthma prediction

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249488
Author(s):  
Kathryn M. Emmerson ◽  
Jeremy D. Silver ◽  
Marcus Thatcher ◽  
Alan Wain ◽  
Penelope J. Jones ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Grass Pollen ◽  
Three Dimensional ◽  
Atmospheric Model ◽  
False Alarms ◽  
Predictive Capacity ◽  
Lightning Strikes ◽  
Large Numbers ◽  
High Concentrations ◽  
Thunderstorm Asthma

The world’s most severe thunderstorm asthma event occurred in Melbourne, Australia on 21 November 2016, coinciding with the peak of the grass pollen season. The aetiological role of thunderstorms in these events is thought to cause pollen to rupture in high humidity conditions, releasing large numbers of sub-pollen particles (SPPs) with sizes very easily inhaled deep into the lungs. The humidity hypothesis was implemented into a three-dimensional atmospheric model and driven by inputs from three meteorological models. However, the mechanism could not explain how the Melbourne event occurred as relative humidity was very low throughout the atmosphere, and most available grass pollen remained within 40 m of the surface. Our tests showed humidity induced rupturing occurred frequently at other times and would likely lead to recurrent false alarms if used in a predictive capacity. We used the model to investigate a range of other possible pollen rupturing mechanisms which could have produced high concentrations of SPPs in the atmosphere during the storm. The mechanisms studied involve mechanical friction from wind gusts, electrical build up and discharge incurred during conditions of low relative humidity, and lightning strikes. Our results suggest that these mechanisms likely operated in tandem with one another, but the lightning method was the only mechanism to generate a pattern in SPPs following the path of the storm. If humidity induced rupturing cannot explain the 2016 Melbourne event, then new targeted laboratory studies of alternative pollen rupture mechanisms would be of considerable value to help constrain the parameterisation of the pollen rupturing process.

Study on the high hydrophobicity and its possible mechanism of textile fabric with structural colors of three-dimensional poly(styrene-methacrylic acid) photonic crystals

RSC Advances ◽  
2015 ◽  
Vol 5 (77) ◽  
pp. 62855-62863 ◽  
Author(s):  
Guojin Liu ◽  
Lan Zhou ◽  
Cuicui Wang ◽  
Yujiang Wu ◽  
Yichen Li ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Methacrylic Acid ◽  
Three Dimensional ◽  
Water Droplets ◽  
Structural Colors ◽  
Textile Fabric

The fabrics with P(St-MAA) photonic crystals possess high hydrophobicity and vivid structural colors. The possible mechanism of hydrophobicity and model of water droplets on the resultant fabric are investigated.

Self-Assembly of Patterned Porous Films from Cyclic Polystyrenes via the Breath Figure Method

2018 ◽  
Vol 122 (7) ◽  
pp. 3926-3933 ◽  
Author(s):  
Bai-Heng Wu ◽  
Lian-Wei Wu ◽  
Kang Gao ◽  
Sen-He Chen ◽  
Zhi-Kang Xu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Porous Films ◽  
Breath Figure ◽  
Breath Figure Method

Tayloring the Photocatalytical Activity of Anatase TiO2 Thin Film Electrodes by Three-Dimensional Mesoporosity

2010 ◽  
Vol 162 ◽  
pp. 91-113 ◽  
Author(s):  
Bernhard Neumann ◽  
Thorsten Brezesinsky ◽  
Bernd Smarsly ◽  
Helmut Tributsch
Keyword(s):  
Thin Film ◽  
Self Assembly ◽  
Three Dimensional ◽  
Great Influence ◽  
X Ray Diffraction ◽  
Porous Films ◽  
X Ray ◽  
Transmission Electron ◽  
Evaporation Induced Self Assembly ◽  
Thin Film Electrodes

Mesoporous titanium dioxide (m-TiO2) thin film electrodes were synthesized by evaporation-induced self-assembly (EISA), utilizing a novel type of amphiphilic block copolymer as template. The ordered network of pores shows an accessible inner volume that results in a huge BET-surface and a distinct transparency. According to X-ray diffraction analyses the mesoporous films are highly crystalline after calcination at 550°C. 1D and 2D small-angle X-ray scattering and transmission electron microscopy investigations prove the high quality of the mesopore texture over micrometer-sized areas. These well-defined, crystalline m-TiO2 films show an increased photoactivity for overall water splitting and oxidation of formic acid as compared to porous films prepared in the same manner without a template. The performance of the electrodes was analyzed by measuring the photocurrent and the mass signal of liberated gas by electrochemical mass spectroscopy (EMS). These experiments reveal that film morphology have a great influence to the I-V characteristic of photoelectrodes. An appropriate crystallization temperature is indispensable to obtain an optimum between crystallinity, morphology and photoactivity and to prevent collapse of the mesopore architecture.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Nanoscale Self-Assembly Using Ion and Electron Beam Techniques: A Rapid Review

MRS Advances ◽  
2020 ◽  
Vol 5 (64) ◽  
pp. 3507-3520
Author(s):  
Chunhui Dai ◽  
Kriti Agarwal ◽  
Jeong-Hyun Cho
Keyword(s):  
Electron Beam ◽  
Self Assembly ◽  
Ion Beam ◽  
Three Dimensional ◽  
The Self ◽  
Stress Generation ◽  
Rapid Review ◽  
High Yield ◽  
3D Nanostructures ◽  
Self Assembled

AbstractNanoscale self-assembly, as a technique to transform two-dimensional (2D) planar patterns into three-dimensional (3D) nanoscale architectures, has achieved tremendous success in the past decade. However, an assembly process at nanoscale is easily affected by small unavoidable variations in sample conditions and reaction environment, resulting in a low yield. Recently, in-situ monitored self-assembly based on ion and electron irradiation has stood out as a promising candidate to overcome this limitation. The usage of ion and electron beam allows stress generation and real-time observation simultaneously, which significantly enhances the controllability of self-assembly. This enables the realization of various complex 3D nanostructures with a high yield. The additional dimension of the self-assembled 3D nanostructures opens the possibility to explore novel properties that cannot be demonstrated in 2D planar patterns. Here, we present a rapid review on the recent achievements and challenges in nanoscale self-assembly using electron and ion beam techniques, followed by a discussion of the novel optical properties achieved in the self-assembled 3D nanostructures.

Reactive Nanopattern in a Triple Structured Bio-Inspired Honeycomb Film as a Clickable Platform

2018 ◽  
Author(s):  
Pierre Marcasuzaa ◽  
Samuel Pearson ◽  
Karell Bosson ◽  
Laurence Pessoni ◽  
Jean-Charles Dupin ◽  
...  
Keyword(s):  
Self Assembly ◽  
Double Porosity ◽  
Surface Groups ◽  
Specific Chemical ◽  
Site Specific ◽  
Surface Functionality ◽  
Wenzel State ◽  
Breath Figure ◽  
Responsive Surfaces ◽  
Secondary Population

A hierarchically structured platform was obtained from spontaneous self-assembly of a poly(styrene)-<i>b</i>-poly(vinylbenzylchloride) (PS-<i>b</i>-PVBC) block copolymer (BCP) during breath figure (BF) templating. The BF process using a water/ethanol atmosphere gave a unique double porosity in which hexagonally arranged micron-sized pores were encircled by a secondary population of smaller, nano-sized pores. A third level of structuration was simultaneously introduced between the pores by directed BCP self-assembly to form out-of-the-plane nano-cylinders, offering very rapid bottom-up access to a film with unprecedented triple structure which could be used as a reactive platform for introducing further surface functionality. The surface nano-domains of VBC were exploited as reactive nano-patterns for site-specific chemical functionalization by firstly substituting the exposed chlorine moiety with azide, then “clicking” an alkyne by copper (I) catalyzed azide-alkyne Huisgen cycloaddition (CuAAC). Successful chemical modification was verified by NMR spectroscopy, FTIR spectroscopy, and XPS, with retention of the micro- and nanostructuration confirmed by SEM and AFM respectively. Protonation of the cyclotriazole surface groups triggered a switch in macroscopic behavior from a Cassie-Baxter state to a Wenzel state, highlighting the possibility of producing responsive surfaces with hierarchical structure.

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