We describe the design and refinement of a high-throughput buckling-based metrology for ascertaining the mechanical properties (e.g., modulus) of combinatorial thin polymer film libraries. We provide critical details for the construction of a suitable strain stage, describe sample preparation, and highlight methods for high-throughput data acquisition and data analysis. To illustrate the combinatorial and high-throughput capability of this metrology, we prepare and evaluate films possessing a gradient in the elastic modulus and compare the results with an analytical expression derived from composite beam theory. Application of this metrology is very simple and practically any laboratory, academic or industrial, can perform such measurements with only modest investment in equipment. Although developed as a platform for investigating combinatorial libraries, researchers can take advantage of the high-throughput nature of this metrology to measure noncombinatorial film specimens as well.
We present a new method for measuring the modulus of soft polymer networks (E < 10 MPa).
This metrology utilizes compression-induced buckling of a sensor film applied to the surface of the specimen,
where the periodic buckling wavelength, assessed rapidly by laser light diffraction or optical microscopy, yields
the modulus of the network specimen. To guide the development of this new technique, we use classical mechanical
analysis to calculate the sensitivity of the critical strain and resulting wavelength of the buckling instability to the
modulus and thickness of the sensor film as well as the modulus of the soft material being probed. Experimental
validation of our technique employed a series of model cross-linked poly(dimethylsiloxane) elastomers. To further
demonstrate the versatility of this method, we measure the moduli of a set of pertinent biomaterials, i.e., cross-linked 2-hydroxyethyl methacrylate (HEMA) hydrogels. Using a hydrogel substrate possessing a gradient in the
cross-link density, we also show how this metrology can be used to map spatial differences and heterogeneity in
modulus within a specimen.
We design V doped NiCoP nanosheets with P vacancies induced by Ar plasma as a cost-effective and bifunctional electrocatalyst for overall water splitting.
The effects of 10 mM putrescine (Put) treated by spraying on leaves on growth, chlorophyll content, photosynthetic gas-exchange characteristics, and chlorophyll fluorescence were investigated by growing cucumber plants (Cucumis sativus L. cv. ChangChun mici) using hydroponics with or without 65 mM NaCl as a salt stress. Salt stress caused the reduction of growth such as leaf area, root volume, plant height, and fresh and dry weights. Furthermore, net photosynthesis rate (P(n)), stomatal conductance (g(s)), intercellular CO(2) concentration (C(i)), and transpiration rate (T(r)) were also reduced by NaCl, but water use efficiency (WUE; P(n)/T(r)) showed a tendency to be enhanced rather than reduced by NaCl. However, Put alleviated the reduction of P (n) by NaCl, and showed a further reduction of C (i) by NaCl. The reduction of g(s) and T(r) by NaCl was not alleviated at all. The enhancement of WUE by NaCl was shown to have no alleviation at day 1 after starting the treatment, but after that, the enhancement was gradually reduced till the control level. Maximum quantum efficiency of PSII (F(v)/F(m)) showed no effects by any conditions based on the combination of NaCl and Put, and in addition, kept constant values in plants grown in each nutrient solution during this experimental period. The efficiency of excitation energy capture by open photosystem II (PSII) (F(v)'/F(m)'), actual efficiency of PSII (Phi(PSII)), and the coefficient on photochemical quenching (qP) of plants with NaCl were reduced with time, and the reduction was alleviated till the control level by treatment with Put. The F(v)'/F(m)', Phi(PSII), and qP of plants without NaCl and/or with Put showed no variation during the experiment. Non-photochemical quenching of the singlet excited state of chlorophyll a (NPQ) showed quite different manner from the others as mentioned above, namely, continued to enhance during the experiment.
Selective doping of optically active ions into the nanocrystalline phase(s) of glass ceramics is of interest for photoluminescence (PL) applications to control the energy transfer (ET) processes between dopants on the nanometer length scale. Here, the focus is on explaining the essential knowledge of the distribution of two groups of active ions: transition metal (Ni2+ and Cr3+) and rare earth (Yb3+ and Er3+) ions, which are doped into i) single‐phase Ga2O3 and ii) dual‐phase Ga2O3 and YF3 nanocrystals (NCs). These NCs are obtained by thermally crystallizing ternary silicate‐ and quinary fluorosilicate‐based glasses, respectively. It is found that the two types of active ions can successfully be doped into Ga2O3 NCs, resulting in enhanced ET between the dopants because of the small separation distance of, e.g., <10 Å, whereas ET is significantly suppressed when Ga2O3 and YF3 NCs are coprecipitated. In this case, the studied rare earth ions have a high propensity for being selectively doped in YF3 NCs. The studied transition‐metal ions can always be found in Ga2O3 NCs irrespective of the presence of the fluoride phase. The selective doping and the ET between the two types of active ions can be controlled simultaneously on annealing. This may allow for the achievement of diverse PL properties, such as ultrabroadband near‐infrared and upconversion‐mediated Stokes emissions.
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