A simple strategy for fabricating honeycomb patterns on commercially available polymer film under a wide humidity range

2020 ◽  
Vol 35 (23-24) ◽  
pp. 3210-3221
Author(s):  
Kai Huang ◽  
Qi Cheng ◽  
Honglei Zhang ◽  
Ligang Lin ◽  
Qiying Wang
Keyword(s):  
Polymer Film ◽  
Simple Strategy ◽  
Humidity Range

Abstract

scholarly journals Photo-Embossed Surface Relief Structures with Improved Aspect Ratios and Their Applications in Liquid Crystal Devices

Polymers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 171
Author(s):  
Xiulan Yang ◽  
Minzhao Gu ◽  
Qunmei Wei ◽  
Yang Zhang ◽  
Sihan Wu ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Visible Light ◽  
Polymer Film ◽  
Surface Relief ◽  
Light Regulation ◽  
Complex Surface ◽  
Economical Method ◽  
Liquid Crystal Devices ◽  
Simple Strategy ◽  
Aspect Ratios

Photo-embossing has been developed as a convenient and economical method for creating complex surface relief structures in polymer films. The pursuit for large aspect ratios of the photo-embossed structures has never stopped. Here, we demonstrate a simple strategy to obtain improved aspect ratios by adding a quick solvent developing step into the photo-embossing process. A good solvent for the monomer is used to remove unreacted monomers from the unexposed region, resulting in deepened valleys of the surface reliefs. In a polymer film as thin as 2.5 µm, the height of the surface reliefs can be increased by a factor of three to around 1.0 µm. This strategy is also shown to be compatible with other methods used to improve the aspect ratios of the photo-embossed structures. Lastly, we employ these surface relief structures in the fabrication of liquid crystal (LC) devices and investigate their performances for visible light regulation.

Dynamics of Nanoparticle Chain Aggregates of Carbon Under Tension

2003 ◽  
Vol 778 ◽  
Author(s):  
Rajdip Bandyopadhyaya ◽  
Weizhi Rong ◽  
Yong J. Suh ◽  
Sheldon K. Friedlander
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Polymer Film ◽  
Elastic Behavior ◽  
Small Strains ◽  
Transmission Electron ◽  
Chain Aggregates ◽  
Nanoparticle Chains ◽  
Reinforcing Filler

AbstractCarbon black in the form of nanoparticle chains is used as a reinforcing filler in elastomers. However, the dynamics of the filler particles under tension and their role in the improvement of the mechanical properties of rubber are not well understood. We have studied experimentally the dynamics of isolated nanoparticle chain aggregates (NCAs) of carbon made by laser ablation, and also that of carbon black embedded in a polymer film. In situ studies of stretching and contraction of such chains in the transmission electron microscope (TEM) were conducted under different maximum values of strain. Stretching causes initially folded NCA to reorganize into a straight, taut configuration. Further stretching leads to either plastic deformation and breakage (at 37.4% strain) or to a partial elastic behavior of the chain at small strains (e.g. 2.3% strain). For all cases the chains were very flexible under tension. Similar reorientation and stretching was observed for carbon black chains embedded in a polymer film. Such flexible and elastic nature of NCAs point towards a possible mechanism of reinforcement of rubber by carbon black fillers.

Hierarchy of π-Stacking Determines the Conformational Preference of Bis-Squaraines

2020 ◽  
Author(s):  
Abhishek Singh ◽  
Reman K. Singh ◽  
G Naresh Patwari
Keyword(s):  
Hydrogen Bonding ◽  
Rational Design ◽  
Biological Molecules ◽  
Conformational Space ◽  
X Ray Crystallography ◽  
Simple Strategy ◽  
Induced Folding ◽  
Π Stacking ◽  
Varying Length ◽  
Dynamics Simulations

The rational design of conformationally controlled foldable modules can lead to a deeper insight into the conformational space of complex biological molecules where non-covalent interactions such as hydrogen bonding and π-stacking are known to play a pivotal role. Squaramides are known to have excellent hydrogen bonding capabilities and hence, are ideal molecules for designing foldable modules that can mimic the secondary structures of bio-molecules. The π-stacking induced folding of bis-squaraines tethered using aliphatic primary and secondary-diamine linkers of varying length is explored with a simple strategy of invoking small perturbations involving the length linkers and degree of substitution. Solution phase NMR investigations in combination with molecular dynamics simulations suggest that bis-squaraines predominantly exist as extended conformations. Structures elucidated by X-ray crystallography confirmed a variety of folded and extended secondary conformations including hairpin turns and 𝛽-sheets which are determined by the hierarchy of π-stacking relative to N–H···O hydrogen bonds.

Hierarchy of π-Stacking Determines the Conformational Preference of Bis-Squaraines

2020 ◽  
Author(s):  
Abhishek Singh ◽  
Reman K. Singh ◽  
G Naresh Patwari
Keyword(s):  
Hydrogen Bonding ◽  
Rational Design ◽  
Biological Molecules ◽  
Conformational Space ◽  
X Ray Crystallography ◽  
Simple Strategy ◽  
Induced Folding ◽  
Π Stacking ◽  
Varying Length ◽  
Dynamics Simulations

The rational design of conformationally controlled foldable modules can lead to a deeper insight into the conformational space of complex biological molecules where non-covalent interactions such as hydrogen bonding and π-stacking are known to play a pivotal role. Squaramides are known to have excellent hydrogen bonding capabilities and hence, are ideal molecules for designing foldable modules that can mimic the secondary structures of bio-molecules. The π-stacking induced folding of bis-squaraines tethered using aliphatic primary and secondary-diamine linkers of varying length is explored with a simple strategy of invoking small perturbations involving the length linkers and degree of substitution. Solution phase NMR investigations in combination with molecular dynamics simulations suggest that bis-squaraines predominantly exist as extended conformations. Structures elucidated by X-ray crystallography confirmed a variety of folded and extended secondary conformations including hairpin turns and 𝛽-sheets which are determined by the hierarchy of π-stacking relative to N–H···O hydrogen bonds.

Internal stresses in plasma deposited polymer film coatings

2018 ◽  
pp. 21-26
Author(s):  
M.P. Danilaev ◽  
◽  
E.A. Bogoslov ◽  
Yu.E. Polsky ◽  
I.V. Yanilkin ◽  
...  
Keyword(s):  
Polymer Film ◽  
Internal Stresses ◽  
Film Coatings

Revealing changes in curcumin bioavailability using vitamin C as an enhancer by HPLC-MS/MS

2019 ◽  
Vol 16 ◽  
Author(s):  
Xufen Dai ◽  
Jiaxue Hao ◽  
Ying Feng ◽  
Jing Wang ◽  
Qiannan Li ◽  
...  
Keyword(s):  
Vitamin C ◽  
High Performance ◽  
Internal Standard ◽  
Fold Increase ◽  
Rat Plasma ◽  
Pharmacokinetic Parameters ◽  
Solution Ph ◽  
Esi Ms ◽  
Simple Strategy ◽  
Isolated Compound

Background: Curcumin (CUR), a natural isolated compound from turmeric, has been the promising star in fighting many diseases but the broad application of curcumin has been limited ascribed to low bioavailability. Objective: The aim of this study is to pursue the enhancement of curcumin bioavailability through co-administration of vitamin C. Methods: Such purpose was achieved through the analysis of curcumin pharmacokinetics by high performance liquid chromatography coupled with electrospray ionization - tandem mass spectrometry (HPLC - ESI - MS/MS). The plasma was separated on a C18 reverse phase column using acetonitrile and ammonium formate solution (pH 6.5; 2.0 mM) at 0.8 mL/min. MS/MS detection was carried out in negative mode using mass patterns of m/z 367.0 > 216.7 for curcumin and m/z 265.2 > 223.9 for internal standard (honokiol). Results: Successful application of the proposed method in the pharmacokinetic study presented clear changes in key pharmacokinetic parameters including the growth of AUC (0-t) up to 2.4 times, 2.2-fold increase of Cmax, 2.2-fold loss of CL, and 1.5-fold diminishment of t1/2. Conclusion: We developed an HPLC-ESI-MS/MS method for determination of curcumin in rat plasma and validated the improvement of bioavailability of curcumin through co-administration of vitamin C. We reasoned these changes to the inhibition of lipid peroxidation induced by the use of vitamin C. Such a simple strategy is possible to become an alternative for enhancing curcumin efficiency in practice.

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