Ultrasensitive Magnetic Tuning of Optical Properties of Films of Cholesteric Cellulose Nanocrystals

ACS Nano ◽  
2020 ◽  
Vol 14 (8) ◽  
pp. 9440-9448 ◽  
Author(s):  
Tianxing Chen ◽  
Qinglan Zhao ◽  
Xin Meng ◽  
Yao Li ◽  
Hui Peng ◽  
...  
Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2564
Author(s):  
Amparo López-Rubio ◽  
Adriana Blanco-Padilla ◽  
Kristiina Oksman ◽  
Sandra Mendoza

In this work, two different strategies for the development of amaranth protein isolate (API)-based films were evaluated. In the first strategy, ultrathin films were produced through spin-coating nanolayering, and the effects of protein concentration in the spin coating solution, rotational speed, and number of layers deposited on the properties of the films were evaluated. In the second strategy, cellulose nanocrystals (CNCs) were incorporated through a casting methodology. The morphology, optical properties, and moisture affinity of the films (water contact angle, solubility, water content) were characterized. Both strategies resulted in homogeneous films with good optical properties, decreased hydrophilic character (as deduced from the contact angle measurements and solubility), and improved mechanical properties when compared with the neat API-films. However, both the processing method and film thickness influenced the final properties of the films, being the ones processed through spin coating more transparent, less hydrophilic, and less water-soluble. Incorporation of CNCs above 10% increased hydrophobicity, decreasing the water solubility of the API films and significantly enhancing material toughness.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jose Luis Orellana ◽  
Derek Wichhart ◽  
Christopher L. Kitchens

The addition of surface-modified cellulose nanocrystals (CNCs) to polymeric matrices can lead to an enhancement of the mechanical and optical properties of host polymers. The use of surfactants can provide an easy and effective way to change the CNC functionality and to evaluate the effects of surface chemistry in the reinforcement mechanisms. In this work, CNCs were solution blended with polylactic acid (PLA) and melt extruded into films. The PLA toughness increased from 1.70 MJ/m3to 2.74 MJ/m3, a 61% increase, with the addition of 1% of decylamine-modified CNCs without a decrease of the tensile strength or modulus. In this work, we investigated the use of two surfactants, decylamine and cetyltrimethylammonium bromide, to enhance CNC compatibility with the hydrophobic PLA matrix. Decylamine at 1.0 wt.% with respect to CNC loading was found to significantly enhance CNC compatibility and property enhancement. The low concentration of surfactant is notable, as other works typically use significantly higher loadings for CNC incorporation and property enhancement. At high CNC concentrations, mechanical properties decreased but the aligned assembly of the CNCs provided intricate colors to the films when observed between crossed polars. The alignment and nanoscale structure of CNCs within the films play an important role in the properties obtained.


2020 ◽  
Vol 11 (4) ◽  
pp. 11797-11816

Cellulose nanomaterials are one of the most relevant scientific-technological discoveries in recent years. Cellulose nanocrystals (CNCs) stand out among them because their extraordinary chemical, mechanical, thermal, and optical properties make them an interesting alternative to manufacture advanced materials from the most abundant biopolymer on Earth. This work presents a critical analysis of the literature published in the last years, emphasizing the various obtaining processes that have emerged in the search for greener methods. A comparative table of the processes used in the extraction of CNCs from various sources (non-edible biomass and agro-industrial wastes) is included, indicating the process’s effectiveness and the characteristics and applications of this sustainable advanced bionanomaterial.


2017 ◽  
Vol 18 (11) ◽  
pp. 2118-2124 ◽  
Author(s):  
Jin Yao ◽  
Haibo Huang ◽  
Long Mao ◽  
Zhihan Li ◽  
Heping Zhu ◽  
...  

Small ◽  
2017 ◽  
Vol 13 (47) ◽  
pp. 1702084 ◽  
Author(s):  
Blaise L. Tardy ◽  
Mariko Ago ◽  
Jiaqi Guo ◽  
Maryam Borghei ◽  
Tero Kämäräinen ◽  
...  

2015 ◽  
Author(s):  
Nathan J. Dawson ◽  
Kyle C. Peters ◽  
Stephen Spinella ◽  
Anthony Maiorana ◽  
Richard A. Gross ◽  
...  

Author(s):  
K. Tsuno ◽  
T. Honda ◽  
Y. Harada ◽  
M. Naruse

Developement of computer technology provides much improvements on electron microscopy, such as simulation of images, reconstruction of images and automatic controll of microscopes (auto-focussing and auto-correction of astigmatism) and design of electron microscope lenses by using a finite element method (FEM). In this investigation, procedures for simulating the optical properties of objective lenses of HREM and the characteristics of the new lens for HREM at 200 kV are described.The process for designing the objective lens is divided into three stages. Stage 1 is the process for estimating the optical properties of the lens. Firstly, calculation by FEM is made for simulating the axial magnetic field distributions Bzc of the lens. Secondly, electron ray trajectory is numerically calculated by using Bzc. And lastly, using Bzc and ray trajectory, spherical and chromatic aberration coefficients Cs and Cc are numerically calculated. Above calculations are repeated by changing the shape of lens until! to find an optimum aberration coefficients.


Author(s):  
A. Strojnik ◽  
J.W. Scholl ◽  
V. Bevc

The electron accelerator, as inserted between the electron source (injector) and the imaging column of the HVEM, is usually a strong lens and should be optimized in order to ensure high brightness over a wide range of accelerating voltages and illuminating conditions. This is especially true in the case of the STEM where the brightness directly determines the highest resolution attainable. In the past, the optical behavior of accelerators was usually determined for a particular configuration. During the development of the accelerator for the Arizona 1 MEV STEM, systematic investigation was made of the major optical properties for a variety of electrode configurations, number of stages N, accelerating voltages, 1 and 10 MEV, and a range of injection voltages ϕ0 = 1, 3, 10, 30, 100, 300 kV).


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