Name: calibration procedures for orthogonal superposition rheology
Uploaded: 2020-11-18T13:00:00
Description: Watch this Scientific Journal Video about Calibration Procedures for Orthogonal Superposition Rheology at JoVE.com

Ran Tao would like to thank funding from the National Institute of Standards and Technology, U.S. Department of Commerce under grant 70NANB15H112. Funding for Aaron M. Forster was provided through congressional appropriations to the National Institute of Standards and Technology.

1. Rheometer setup
NOTE: The protocol in this section describes basic steps to run a rheology experiment (for either a separate motor-transducer rheometer or a combined motor-transducer rheometer), including preparation of the setup, installation of appropriate geometry, loading the test material, setting up the experiment procedure, specifying the geometry, and starting the test. Specific instructions and notes are provided for OSP operation. To minimize thermal gradients in the transducer, it ...

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Y. C., Ness, C., Cates, M. E., Sun, J., Cohen, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tunable+shear+thickening+in+suspensions.">Tunable shear thickening in suspensions.</a> Proceedings of the National Academy of Sciences. 113 (39), 10774-10778 (2016).</li><li>Gracia-Fern&#225;ndez, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+application+of+electro+and+orthogonal+superposition+rheology+on+a+starch/silicone+oil+suspension.">Simultaneous application of electro and orthogonal superposition rheology on a starch/silicone oil suspension.</a> Journal of Rheology. 60 (1), 121-127 (2015).</li><li>Sung, S. H., Kim, S., Hendricks, J., Clasen, C., Ahn, K. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Orthogonal+superposition+rheometry+of+colloidal+gels:+time-shear+rate+superposition.">Orthogonal superposition rheometry of colloidal gels: time-shear rate superposition.</a> Soft Matter. 14 (42), 8651-8659 (2018).</li><li>Colombo, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superposition+rheology+and+anisotropy+in+rheological+properties+of+sheared+colloidal+gels.">Superposition rheology and anisotropy in rheological properties of sheared colloidal gels.</a> Journal of Rheology. 61 (5), 1035-1048 (2017).</li><li>Jacob, A. R., Poulos, A. S., Kim, S., Vermant, J., Petekidis, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convective+Cage+Release+in+Model+Colloidal+Glasses.">Convective Cage Release in Model Colloidal Glasses.</a> Physical Review Letters. 115 (21), 218301 (2015).</li><li>Jacob, A. R., Poulos, A. S., Semenov, A. N., Vermant, J., Petekidis, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+dynamics+of+concentrated+starlike+micelles:+A+superposition+rheometry+investigation+into+relaxation+mechanisms.">Flow dynamics of concentrated starlike micelles: A superposition rheometry investigation into relaxation mechanisms.</a> Journal of Rheology. 63 (4), 641-653 (2019).</li><li>Moghimi, E., Vermant, J., Petekidis, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Orthogonal+superposition+rheometry+of+model+colloidal+glasses+with+short-ranged+attractions.">Orthogonal superposition rheometry of model colloidal glasses with short-ranged attractions.</a> Journal of Rheology. 63 (4), 533-546 (2019).</li><li>Tao, R., Forster, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=End+effect+correction+for+orthogonal+small+strain+oscillatory+shear+in+a+rotational+shear+rheometer.">End effect correction for orthogonal small strain oscillatory shear in a rotational shear rheometer.</a> Rheologica Acta. 59 (2), 95-108 (2020).</li><li>Schrag, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deviation+of+velocity+gradient+profiles+from+the+"gap+loading"+and+"surface+loading"+limits+in+dynamic+simple+shear+experiments.">Deviation of velocity gradient profiles from the "gap loading" and "surface loading" limits in dynamic simple shear experiments.</a> Transactions of the Society of Rheology. 21 (3), 399-413 (1977).</li><li>Ewoldt, R. H., Johnston, M. T., Caretta, L. 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In this protocol, we present a detailed experimental procedure for performing viscosity calibration measurements using Newtonian fluids for a commercial orthogonal superposition rheology technique with a double-wall concentric cylinder geometry. The calibration factors, i.e., the primary end-effect factor CL and the orthogonal end-effect factor CLo, are determined independently by conducting steady shear rate sweep and orthogonal frequency sweep tests. After obtai...

Understanding the rheological properties of complex fluids is essential to many industries for the development and manufacture of reliable and reproducible products1. These &#8220;complex fluids&#8221; include suspensions, polymeric liquids, and foams that widely exist in our everyday life, for example, in personal care products, foods, cosmetics, and household products. The rheological or flow properties (e.g., viscosity) are key quantities&#160;of interest in establishing performance metrics for end use and processability, but flow properties are interconnected with the microstructures that exist within complex fluids. One prominent characteristic of complex fluids that distinguishes them from simple liquids is that they possess diverse microstructures spanning multiple length scales2. Those microstructures can be easily affected by different flow conditions, which, in turn, result in changes in their macroscopic properties. Unlocking this structure-property loop via non-linear viscoelastic behavior of complex fluids in response to flow and deformation remains a challenging task for experimental rheologists.
Orthogonal superposition (OSP) rheology3 is a robust technique to address this measurement challenge. In this technique, a small amplitude oscillatory shear flow is superimposed orthogonally to a unidirectional primary steady-shear flow, which enables the simultaneous measurement of a viscoelastic relaxation spectrum under the imposed primary shear flow. To be more specific, the small oscillatory shear perturbation can be analyzed using theories in linear viscoelasticity4, while the non-linear flow condition is achieved by the primary steady-shear flow. As the two flow fields are orthogonal and thus not coupled, the perturbation spectra can be directly related to the variation of the microstructure under the primary non-linear flow5. This advanced measurement technique offers an opportunity to elucidate structure-property-processing relationships in complex fluids to optimize their formulation, processing, and application.
The implementation of modern OSP rheology was not the result of a sudden epiphany; rather, it is based on many decades of development of custom devices. The first custom made OSP apparatus is dated back to 1966 by Simmons6, and many efforts were made thereafter7,8,9,10. Those early custom-built devices suffer from many drawbacks such as alignment issues, the pumping flow effect (due to the axial movement of the bob to provide orthogonal oscillation), and limits to instrument sensitivity. In 1997, Vermant et al.3 modified the force rebalance transducer (FRT) on a commercial separate motor-transducer rheometer, which enabled OSP measurements for fluids with a wider viscosity range than previous devices. This modification enables the normal force rebalance transducer to function as a stress-controlled rheometer, imposing an axial oscillation in addition to a measurement of the axial force. Recently, the geometries required for OSP measurements, after the methodology by Vermant, have been released for a commercial separate motor-transducer rheometer.
Since the advent of commercial OSP rheology, there is a growing interest in applying this technique for the investigation of various complex fluids. Examples include colloidal suspensions11,12, colloidal gels13,14 and glasses15,16,17. While the availability of the commercial instrument promotes OSP research, the complicated OSP geometry requires a deeper understanding of the measurement than other routine rheological techniques. The OSP flow cell is based on a double-wall concentric cylinder (or Couette) geometry. It features an open top and open bottom design to enable fluid to flow back and forth between the annular gaps and the reservoir. Despite the optimization made to the geometry design by the manufacturer, when undergoing OSP operation the fluid experiences an inhomogeneous flow field, geometric end effects, and residual pumping flow, all of which can introduce substantial experimental error. Our previous work18 reported important end-effect correction procedures using Newtonian fluids for this technique. To obtain correct viscosity results, appropriate end-effect factors in both primary and orthogonal directions should be applied. In this protocol, we aim to present a detailed calibration methodology for the OSP rheological technique and provide recommendations for best practices to reduce measurement errors. The procedures delineated in this paper on OSP geometry setup, sample loading, and OSP test settings should be easily adoptable and translated for non-Newtonian fluids measurements. We advise that users utilize the calibration procedures described here to determine the end-effect correction factors for their applications prior to OSP measurements on any fluid classification (Newtonian or Non-Newtonian). We note that the calibration procedures for end factors have not been reported previously. The protocol provided in the present paper also describes step-by-step guide and tips on how to perform accurate rheological measurements in general and the technical resource on the understanding of &#8220;raw&#8221; data versus &#8220;measured&#8221; data, which may be overlooked by rheometer users.

<table>
	<tbody>
		<tr>
			<td>Advanced Peltier System</td>
			<td>TA Instruments</td>
			<td>402500.901</td>
			<td>Enviromental control device</td>
		</tr>
		<tr>
			<td>ARES-G2 Rheometer</td>
			<td>TA Instruments</td>
			<td>401000.501</td>
			<td>Rheometer</td>
		</tr>
		<tr>
			<td>Brookfield Silicone Fluid, 12500cP</td>
			<td>AMTEK Brookfield</td>
			<td>12500 cps</td>
			<td>Viscosity standard liquid</td>
		</tr>
		<tr>
			<td>OSP Slotted Bob, 33 mm</td>
			<td>TA Instruments</td>
			<td>402796.902</td>
			<td>Bob, upper geometry</td>
		</tr>
		<tr>
			<td>OSP Slotted Double Gap Cup, 34 mm</td>
			<td>TA Instruments</td>
			<td>402782.901</td>
			<td>Double wall cup, lower geometry</td>
		</tr>
		<tr>
			<td>Pipette (1 &#8211; 10 mL)</td>
			<td>Eppendorf</td>
			<td>3120000089</td>
			<td>To load test materials</td>
		</tr>
		<tr>
			<td>Pipette (100 &#8211; 1,000 &#181;L)</td>
			<td>Eppendorf</td>
			<td>3123000063</td>
			<td>To load test materials</td>
		</tr>
		<tr>
			<td>Pipette Tips (0.5 &#8211; 10 mL)</td>
			<td>Eppendorf</td>
			<td>022492098</td>
			<td>To load test materials</td>
		</tr>
		<tr>
			<td>Pipette Tips (50 &#8211; 1,000 &#181;L)</td>
			<td>Eppendorf</td>
			<td>022491555</td>
			<td>To load test materials</td>
		</tr>
		<tr>
			<td>Spatula</td>
			<td>VWR</td>
			<td>82027-532</td>
			<td>To load test materials</td>
		</tr>
		<tr>
			<td>TRIOS</td>
			<td>TA Instruments</td>
			<td>v4.3.1.39215</td>
			<td>Rheometer software</td>
		</tr>
	</tbody>
</table>

calibration procedures for orthogonal superposition rheology

Orthogonal superposition (OSP) rheology is an advanced rheological technique that involves superimposing a small-amplitude oscillatory shear deformation orthogonal to a primary shear flow. This technique allows the measurement of structural dynamics of complex fluids under non-linear flow conditions, which is important for the understanding and prediction of the performance of a wide range of complex fluids. The OSP rheological technique has a long history of development since the 1960s, mainly through the custom-built devices that highlighted the power of this technique. The OSP technique is now commercially available to the rheology community. Given the complicated design of the OSP geometry and the non-ideal flow field, users should understand the magnitude and sources of measurement error. This study presents calibration procedures using Newtonian fluids that includes recommendations for best practices to reduce measurement errors. Specifically, detailed information on the end-effect factor determination method, sample filling procedure, and identification of the appropriate measurement range (e.g., shear rate, frequency, etc.) are provided.

Representative results from the viscosity calibration measurements on a 12.2 Pa s silicone viscosity standard are represented in Figure 5 and Figure 6. Note that the primary end-effect factor and the orthogonal end-effect factor are both set to 1.00 for the calibration runs. Figure 5 shows the steady shear viscosity and the torque as a function of shear rate on a double y-axis plot. The silicone liquid is a Newtonian fluid; as expec...

Watch this Scientific Journal Video about Calibration Procedures for Orthogonal Superposition Rheology at JoVE.com

Calibration Procedures for Orthogonal Superposition Rheology

We present a detailed calibration protocol for a commercial orthogonal superposition rheology technique using Newtonian fluids including end-effect correction factor determination methods and recommendations for best practices to reduce experimental error.

Orthogonal superposition (OSP) rheology is an advanced rheological technique that involves superimposing a small-amplitude oscillatory shear deformation ...

Orthogonal Superposition Radiology is an advanced technique that allows the measurement of radiological properties of complex fluids under non-linear flow conditions, which offer insights into the micro-structural changes that governs macroscopic properties. The information gained on the structured property processing relationships in complex fluids is important to many industries for the development and manufacturer of reliable products. OSP is now commercially available for the radiology community.Given the complicated geometry design, a protocol to quantify measurement error is critical to the successful use of this technique. The calibration protocol described in this video is the first standard operating procedure to properly determine the end effect factors, a proper accounting of the end effect factors reduces measurement error. Before installing the geometry, enable the orthogonal superposition feature in the rheometer software.After lifting the stage to maximum height, install a lower platinum resistance thermometer on the test station for temperature measurement and an environmental control device. Assemble the inner and outer cylinders, to complete the double wall cup configuration. Insert the cup into the environmental control device and align the geometry.Press the lower geometry cup downward to compress the spring-loaded platinum resistance thermometer, by using a torque screwdriver to tighten the thumbscrew. Disable the motor power and use a finger to spin the geometry to confirm that the cup rotates freely. Install the upper geometry bob onto the transducer shaft, and click the tear transducer button in the transducer control panel of the rheometer software to tear the normal force and torque.Then click the zero fixture button to zero the gap between the upper and lower geometries. To load the test material, lift the stage to provide enough workspace to load the test material into the cup, and carefully load the test material into the cup. Lower the upper geometry carefully into the fluid to reach the geometry gap set point of eight millimeters.When the bob end contacts the fluid, reduce the downward velocity of the bob. Lift the bob vertically to a position at which the wetted fluid contact line can be visually inspected. Carefully lift the bob to the previous loading position to allow enough workspace and load an additional amount of test material into the cup as needed.Lower the upper geometry into the fluid, and use the go-to geometry gap button to set the cup and final geometry gap. Repeat the adjustment until the wetted contact line on the bob is approximately two millimeters above the lower end of the upper bob opening. Then move the bob to the geometry gap set point and allow the test material to relax.To verify that the correct geometry has been selected, open the orthogonal double wall concentric cylinder geometry. If the orthogonal superposition radiology geometry is not listed, manually create a new geometry with the software, using the dimensions for the geometry as indicated in the table. Then specify the geometry constants, including the inertia and upper tool mass, and enter one for both the end effect factor, and orthogonal end effect factor.To perform a steady sheer rate sweep test, condition the sample at 25 degrees Celsius for 15 minutes. When the test material has reached thermal equilibrium, under the procedure tab in the rheometer software select flow and sweep. In the environmental control window, set the test temperature to 25 degrees Celsius.Set the sheer rate range from 0.01 to 100 inverse seconds, with data recording at 10 points per decade, logarithmically, and enable automatic steady state determination. Then start the experiment. To perform an orthogonal frequency sweep test, set the normal force transducer to conditioning and transducer mode.And condition the sample at 25 degrees Celsius for 15 minutes to ensure thermal equilibration. Select the orthogonal frequency sweep test with the test temperature set to 25 degrees Celsius. Specify the desired normal strain and enter zero inverse seconds for the sheer rate in the rotational direction.Then specify the angular frequency range from 0.1 to 40 rads per second at 10 points per decade, logarithmically, and start the experiment. To verify that the corrections are valid, using the calibrated end effect factors obtained from the calibration experiments, enter the calibrated values for the end effect factor and orthogonal end effect factor under the geometry constants. The stress constants will be automatically updated.Then set up an orthogonal frequency sweep test as demonstrated, using one inverse second for the shear rate and start the experiment. Here, representative results from the viscosity calibration measurements on a 12.2 pascal-second silicone viscosity standard are shown. The silicone liquid is a newtonian fluid with an expected constant viscosity independent of the applied shear rate.The measured torque increases linearly as the sheer rate increases and all of the data are above the low torque limit. The uncorrected viscosity value is higher than the actual viscosity. These orthogonal frequency sweep tests demonstrate different orthogonal strain amplitudes from 0.5 to 9.4%for the 12.2 pascal-second viscosity standard.Similarly, without correction, the measured orthogonal complex viscosity overestimates the actual viscosity of 12.2 pascal-second. Only the viscosity data with corresponding orthogonal force values above the lower limit of the axial oscillation force for the transducer, are used to calculate the average viscosity for correction. To calculate the end effect factors here, the primary in effect factor is equal to the uncorrected primary viscosity divided by the viscosity of the standard liquid.The orthogonal end effect factor is equal to the viscosity of the standard liquid divided by the uncorrected orthogonal viscosity. Here, an orthogonal superposition measurement was performed under steady shear for viscosity verification check. Only the data with values greater than the instrument force resolution were plotted.Since the correct and effect factors were applied, the measured viscosities in both directions matched the accepted oil viscosity value of 12.2 pascal-seconds. Now, you should have a good understanding of how to perform calibration for OSP using newtonian fluids. We recommend that users determine their end effect correction factors for their own instruments and geometries because the actual corrections are material and instrument dependent.Making accurate measurements are important for scientific research as well as product development. This protocol provides a technical resource for the instrument users and also guidance to manufacturers for optimizing the engineering design of future instruments.

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Bringing the Visible Universe into Focus with Robo-AO

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Astronomical adaptive-optics systems compensate for the effects of atmospheric turbulence. First, the shape of the incoming non-planar wave is determined using measurements of a nearby bright star by a wavefront sensor. Next, an element in the optical system, such as a deformable mirror, is commanded to correct the shape of the incoming light wave. Additional corrections are made at a rate sufficient to keep up with the dynamically changing atmosphere through which the telescope looks, ultimately producing diffraction-limited images.
The fidelity of the wavefront sensor measurement is based upon how well the incoming light is spatially and temporally sampled1. Finer sampling requires brighter reference objects. While the brightest stars can serve as reference objects for imaging targets from several to tens of arc seconds away in the best conditions, most interesting astronomical targets do not have sufficiently bright stars nearby. One solution is to focus a high-power laser beam in the direction of the astronomical target to create an artificial reference of known shape, also known as a 'laser guide star'. The Robo-AO laser adaptive optics system2,3 employs a 10-W ultraviolet laser focused at a distance of 10 km to generate a laser guide star. Wavefront sensor measurements of the laser guide star drive the adaptive optics correction resulting in diffraction-limited images that have an angular resolution of ~0.1 arc seconds on a 1.5-m telescope.

Light from astronomical objects must travel through the earth's turbulent atmosphere before it can be imaged by ground-based telescopes. To enable direct imaging at maximum theoretical angular resolution, advanced techniques such as those employed by the Robo-AO adaptive-optics system must be used.

The angular  resolution of ground-based optical telescopes is limited by the degrading  effects of the turbulent atmosphere. In the absence of an ...

Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM

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Because of the importance and extensive use of palladium, gold and cobalt metals in high-technology equipment, their recovery and recycling constitute an important industrial challenge. The metal recovery system described herein is a simple, low-cost means for the effective detection, removal, and recovery of these metals from the urban mine.

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in ...

Dielectric RheoSANS &#8212; Simultaneous Interrogation of Impedance, Rheology and Small Angle Neutron Scattering of Complex Fluids

A procedure for the operation of a new dielectric RheoSANS instrument capable of simultaneous interrogation of the electrical, mechanical and microstructural properties of complex fluids is presented. The instrument consists of a Couette geometry contained within a modified forced convection oven mounted on a commercial rheometer. This instrument is available for use on the small angle neutron scattering (SANS) beamlines at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR). The Couette geometry is machined to be transparent to neutrons and provides for measurement of the electrical properties and microstructural properties of a sample confined between titanium cylinders while the sample undergoes arbitrary deformation. Synchronization of these measurements is enabled through the use of a customizable program that monitors and controls the execution of predetermined experimental protocols. Described here is a protocol to perform a flow sweep experiment where the shear rate is logarithmically stepped from a maximum value to a minimum value holding at each step for a specified period of time while frequency dependent dielectric measurements are made. Representative results are shown from a sample consisting of a gel composed of carbon black aggregates dispersed in propylene carbonate. As the gel undergoes steady shear, the carbon black network is mechanically deformed, which causes an initial decrease in conductivity associated with the breaking of bonds comprising the carbon black network. However, at higher shear rates, the conductivity recovers associated with the onset of shear thickening. Overall, these results demonstrate the utility of the simultaneous measurement of the rheo-electro-microstructural properties of these suspensions using the dielectric RheoSANS geometry.

Here, we present a procedure for the measurement of simultaneous impedance, rheology and neutron scattering from soft matter materials under shear flow.

A procedure for the operation of a new dielectric RheoSANS instrument capable of simultaneous interrogation of the electrical, mechanical and ...

Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection

The ability to perform simultaneous resonant excitation and fluorescence detection is important for quantum optical measurements of quantum dots (QDs). Resonant excitation without fluorescence detection &#8211; for example, a differential transmission measurement &#8211; can determine some properties of the emitting system, but does not allow applications or measurements based on the emitted photons. For example, the measurement of photon correlations, observation of the Mollow triplet, and realization of single photon sources all require collection of the fluorescence. Incoherent excitation with fluorescence detection &#8211; for example, above band-gap excitation &#8211; can be used to create single photon sources, but the disturbance of the environment due to the excitation reduces the indistinguishability of the photons. Single photon sources based on QDs will have to be resonantly excited to have high photon indistinguishability, and simultaneous collection of the photons will be necessary to make use of them. We demonstrate a method to resonantly excite a single QD embedded in a planar cavity by coupling the excitation beam into this cavity from the cleaved face of the sample while collecting the fluorescence along the sample&#39;s surface normal direction. By carefully matching the excitation beam to the waveguide mode of the cavity, the excitation light can couple into the cavity and interact with the QD. The scattered photons can couple to the Fabry-Perot mode of the cavity and escape in the surface normal direction. This method allows complete freedom in the detection polarization, but the excitation polarization is restricted by the propagation direction of the excitation beam. The fluorescence from the wetting layer provides a guide to align the collection path with respect to the excitation beam. The orthogonality of the excitation and detection modes enables resonant excitation of a single QD with negligible laser scattering background.

Resonant excitation of a single self-assembled quantum dot can be achieved using an excitation mode orthogonal to the fluorescence collection mode. We demonstrate a method using the waveguide and Fabry-Perot modes of a planar microcavity surrounding the quantum dots. The method allows complete freedom in the detection polarization.

The ability to perform simultaneous resonant excitation and fluorescence detection is important for quantum optical measurements of quantum dots (QDs). ...

Fabrication Procedures and Birefringence Measurements for Designing Magnetically Responsive Lanthanide Ion Chelating Phospholipid Assemblies

Bicelles are tunable disk-like polymolecular assemblies formed from a large variety of lipid mixtures. Applications range from membrane protein structural studies by nuclear magnetic resonance (NMR) to nanotechnological developments including the formation of optically active and magnetically switchable gels. Such technologies require high control of the assembly size, magnetic response and thermal resistance. Mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and its lanthanide ion (Ln3+) chelating phospholipid conjugate, 1,2-dimyristoyl-sn-glycero-3-phospho-ethanolamine-diethylene triaminepentaacetate (DMPE-DTPA), assemble into highly magnetically responsive assemblies such as DMPC/DMPE-DTPA/Ln3+ (molar ratio 4:1:1) bicelles. Introduction of cholesterol (Chol-OH) and steroid derivatives in the bilayer results in another set of assemblies offering unique physico-chemical properties. For a given lipid composition, the magnetic alignability is proportional to the bicelle size. The complexation of Ln3+ results in unprecedented magnetic responses in terms of both magnitude and alignment direction. The thermo-reversible collapse of the disk-like structures into vesicles upon heating allows tailoring of the assemblies&#39; dimensions by extrusion through membrane filters with defined pore sizes. The magnetically alignable bicelles are regenerated by cooling to 5 &#176;C, resulting in assembly dimensions defined by the vesicle precursors. Herein, this fabrication procedure is explained and the magnetic alignability of the assemblies is quantified by birefringence measurements under a 5.5 T magnetic field. The birefringence signal, originating from the phospholipid bilayer, further enables monitoring of polymolecular changes occurring in the bilayer. This simple technique is complementary to NMR experiments that are commonly employed to characterize bicelles.

Fabrication procedures for highly magnetically responsive lanthanide ion chelating polymolecular assemblies are presented. The magnetic response is dictated by the assembly size, which is tailored by extrusion through nanopore membranes. The assemblies&#39; magnetic alignability and temperature-induced structural changes are monitored by birefringence measurements, a complimentary technique to nuclear magnetic resonance and small angle neutron scattering.

Bicelles are tunable disk-like polymolecular assemblies formed from a large variety of lipid mixtures. Applications range from membrane protein structural ...

Atmospheric Pressure Fabrication of Large-Sized Single-Layer Rectangular SnSe Flakes

Tin selenide (SnSe) belongs to the family of layered metal chalcogenide materials with a buckled structure like phosphorene, and has shown potential for applications in two-dimensional nanoelectronics devices. Although many methods to synthesize SnSe nanocrystals have been developed, a simple way to fabricate large-sized single-layer SnSe flakes remains a great challenge. Herein, we show the experimental method to directly grow large-sized single-layer rectangular SnSe flakes on commonly used SiO2/Si insulating substrates using a straightforward two-step fabrication method in an atmospheric pressure quartz tube furnace system. The single-layer rectangular SnSe flakes with an average thickness of ~6.8 &#197; and lateral dimensions of about 30 &#181;m &#215; 50 &#181;m were fabricated by a combination of vapor transport deposition technique and nitrogen etching route. We characterized the morphology, microstructure, and electrical properties of the rectangular SnSe flakes and obtained excellent crystallinity and good electronic properties. This article about the two-step fabrication method can help researchers grow other similar two-dimensional, large-sized, single-layer materials using an atmospheric pressure system.

A protocol is presented demonstrating a two-step fabrication technique to grow large-sized single-layer rectangular shaped SnSe flakes on low-cost SiO2/Si dielectrics wafers in an atmospheric pressure quartz tube furnace system.

Tin selenide (SnSe) belongs to the family of layered metal chalcogenide materials with a buckled structure like phosphorene, and has shown potential for ...

Hybrid Printing for the Fabrication of Smart Sensors

A method to combine additively manufactured substrates or foils and multilayer inkjet printing for the fabrication of sensor devices is presented. First, three substrates (acrylate, ceramics, and copper) are prepared. To determine the resulting material properties of these substrates, profilometer, contact angle, scanning electron microscope (SEM), and focused ion beam (FIB) measurements are done. The achievable printing resolution and suitable drop volume for each substrate are, then, found through the drop size tests. Then, layers of insulating and conductive ink are inkjet printed alternately to fabricate the target sensor structures. After each printing step, the respective layers are individually treated by photonic curing. The parameters used for the curing of each layer are adapted depending on the printed ink, as well as on the surface properties of the respective substrate. To confirm the resulting conductivity and to determine the quality of the printed surface, four-point probe and profilometer measurements are done. Finally, a measurement set-up and results achieved by such an all-printed sensor system are shown to demonstrate the achievable quality.

Here we present a protocol for the fabrication of inkjet-printed multilayer sensor structures on additively manufactured substrates and foil.

A method to combine additively manufactured substrates or foils and multilayer inkjet printing for the fabrication of sensor devices is presented. First, ...

Cutting Procedures, Tensile Testing, and Ageing of Flexible Unidirectional Composite Laminates

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, where the yarns in each layer are oriented parallel to each other and held in place using binder resins and thin polymer films. The armor is constructed by stacking the unidirectional layers in different orientations. To date, only very preliminary work has been performed to characterize the ageing of the binder resins used in unidirectional laminates and the effects on their performance. For example, during the development of the conditioning protocol used in the National Institute of Justice Standard-0101.06, UD laminates showed visual signs of delamination and reductions in V50, which is the velocity at which half of the projectiles are expected to perforate the armor, after ageing. A better understanding of the material property changes in UD laminates is necessary to comprehend the long-term performance of armors constructed from these materials. There are no current standards recommended for mechanically interrogating unidirectional (UD) laminate materials. This study explores methods and best practices for accurately testing the mechanical properties of these materials and proposes a new test methodology for these materials. Best practices for ageing these materials are also described.

The goal of the study was to develop protocols to prepare consistent specimens for accurate mechanical testing of high-strength aramid or ultra-high-molar-mass polyethylene-based flexible unidirectional composite laminate materials and to describe protocols for performing artificial ageing on these materials.

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, ...

Procedure for the Transfer of Polymer Films Onto Porous Substrates with Minimized Defects

The fabrication of devices containing thin film composite membranes necessitates the transfer of these films onto the surfaces of arbitrary support substrates. Accomplishing this transfer in a highly controlled, mechanized, and reproducible manner can eliminate the creation of macroscale defect structures (e.g., tears, cracks, and wrinkles) within the thin film that compromise device performance and the usable area per sample. Here, we describe a general protocol for the highly controlled and mechanized transfer of a polymeric thin film onto an arbitrary porous support substrate for eventual use as a water filtration membrane device. Specifically, we fabricate a block copolymer (BCP) thin film on top of a sacrificial, water-soluble poly(acrylic acid) (PAA) layer and silicon wafer substrate. We then utilize a custom-designed, 3D-printed transfer tool and drain chamber system to deposit, lift-off, and transfer the BCP thin film onto the center of a porous anodized aluminum oxide (AAO) support disc. The transferred BCP thin film is shown to be consistently placed onto the center of the support surface due to the guidance of the meniscus formed between the water and the 3D-printed plastic drain chamber. We also compare our mechanized transfer-processed thin films to those that have been transferred by hand with the use of tweezers. Optical inspection and image analysis of the transferred thin films from the mechanized process confirm that little-to-no macroscale inhomogeneities or plastic deformations are produced, as compared to the multitude of tears and wrinkles produced from manual transfer by hand. Our results suggest that the proposed strategy for thin film transfer can reduce defects when compared to other methods across many systems and applications.

We present a procedure for highly controlled and wrinkle-free transfer of block copolymer thin films onto porous support substrates using a 3D-printed drain chamber. The drain chamber design is of general relevance to all procedures involving transfer of macromolecular films onto porous substrates, which is normally done by hand in an irreproducible fashion.

The fabrication of devices containing thin film composite membranes necessitates the transfer of these films onto the surfaces of arbitrary support ...