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Etching rate, polarity, and PDMS swelling index of different solvents. The etching rate of a circular channel as was measured by fl owing through the channel a 0.17 M of TBAF solution in 16 different organic solvents. Each solvent is further described by the polarity index, as a measurement for TBAF dissolution and reactivity, by the swelling index of PDMS.
Source publication
Polydimethyl siloxane (PDMS) is the most widely used polymer in microfluidic devices. Microfluidic devices are used in all ranges of science. The microstructure of a microfluidic device influences its efficiency. One method for controlling microstructure is through wet etching. A particularly common etchant is tetrabutylammonium fluoride (TBAF). Th...
Contexts in source publication
Context 1
... included polar, nonpolar, protic, and aprotic solvents. (Table 1 Aaron P. Esser-Kahn was born and raised in Bloomfi eld Hills, MI. As a high-school student, he began his interest in research at Wayne State University. ...
Context 2
... swelling index of PDMS, previously described by Whitesides and co-workers, [ 20 ] which should correlate with more effi cient penetration of the active fl uoride into the cross-linked polymer chains. (Table 1 ) While the etching rate is generally higher in more polar and better swelling solvents, there are several exceptions that encouraged us to investigate each parameter separately. ...
Citations
... As shown in Figure 6a, we can find only the FT-IR peaks from the solvents remaining inside of the CsPbI2Br thin film. This observation indicates that the trace amounts of the solvent molecules may survive in the trapped state inside of the perovskite film, although the annealing temperature (>250 °C) could also be trapped into the crystal structure of CsPbI2Br, although CB and CsPbI2Br have two different polarities, i.e., CB is slightly polar (polarity index = 2.7) but CsPbI2Br and DMSO (polarity index = 7.2) are highly polar [63]. Hence, CB's trapping could be understood based on the physical trap instead of the chemical affinity between the CB and the CsPbI2Br perovskite. ...
... However, for the case of CB, the 'solvent-antisolvent' (DMSO and CB) molecules are miscible because of the entropy-driven mixing, affording CB to wash and remove the DMSO molecules during its dripping process [35]. However, when CB was dropped on top of the wet perovskite precursor film, CB could also be trapped into the crystal structure of CsPbI 2 Br, although CB and CsPbI 2 Br have two different polarities, i.e., CB is slightly polar (polarity index = 2.7) but CsPbI 2 Br and DMSO (polarity index = 7.2) are highly polar [63]. Hence, CB's trapping could be understood based on the physical trap instead of the chemical affinity between the CB and the CsPbI 2 Br perovskite. ...
All-inorganic perovskite semiconductors have received significant interest for their potential stability over heat and humidity. However, the typical CsPbI3 displays phase instability despite its desirable bandgap of ~1.73 eV. Herein, we studied the mixed halide perovskite CsPbI2Br by varying the silver doping concentration. For this purpose, we examined its bandgap tunability as a function of the silver doping by using density functional theory. Then, we studied the effect of silver on the structural and optical properties of CsPbI2Br. Resultantly, we found that ‘silver doping’ allowed for partial bandgap tunability from 1.91 eV to 2.05 eV, increasing the photoluminescence (PL) lifetime from 0.990 ns to 1.187 ns, and, finally, contributing to the structural stability when examining the aging effect via X-ray diffraction. Then, through the analysis of the intermolecular interactions based on the solubility parameter, we explain the solvent engineering process in relation to the solvent trapping phenomena in CsPbI2Br thin films. However, silver doping may induce a defect morphology (e.g., a pinhole) during the formation of the thin films.
... As mentioned, the luminescence intensity of the complex increased in the order methanol > ethanol > acetonitrile > water and was inversely proportional to the polarity index of the solvent (water = 10.2; acetonitrile = 5.8; ethanol = 5.2; and methanol = 5.1) [61]. The polarity index is defined as a measure of the degree of interaction between the solvent and the polar solute. ...
A novel ligand, namely, (N’,N’’’-((1E,2E)-1,2-diphenylethane-1,2-diylidene)bis(3-allyl-2-hydroxybenzohydrazide) (H2DBAZ), was designed and synthesized. This ligand demonstrated the ability to successfully interact with Tb(III) ions, resulting in the formation of a chemosensor that exhibited luminescent properties. The novel ligand was produced and subsequently subjected to characterization with several analytical techniques, including mass spectroscopy, elemental analysis, Fourier-transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance spectroscopy (1H NMR). The postulated chemical structure of the Tb(III)–(DBAZ) complex was assessed utilizing a molar ratio approach. The chemosensor exhibited both selectivity and sensitivity towards malathion when compared to other nine organophosphorus pesticides that were investigated in methanol. The method was based on the phenomenon of luminescence static quenching shown by the complex subsequent to its interaction with the malathion pesticide. A linear Stern–Volmer plot was seen and, subsequently, utilized to generate the calibration curve. The observed linear range spanned from 0.39 to 60 µM, with a strong correlation coefficient of 0.999. Additionally, the limit of detection (LOD) was determined to be 0.118 µM. This methodology was successfully employed to measure the presence of malathion in various water samples. This particular complex exhibited promising potential for application in the development of a chemosensor utilizing the molecularly imprinted polymer approach.
... Similarly, water behaved as the most interactive solvent with PEI sublayers in < 64 > and < 128 > layered structures (Fig. S12). The difference in PEI dissolution rates was correlated to (i) the etchant molecular size (i.e., water = 0.28 nm, ethanol = 0.44 nm, and IPA = 0.6 nm), i.e., the smaller the molecular size of the solvent, the faster the diffusion and polymer swelling [80,81]; (ii) polarity of the solvent (polarity index (PI) of water = 10.2, ethanol = 5.2, and IPA = 3.9), i.e., the solvent with higher PI indicates high polarity and ability to dissolve highly polar compounds (PEI) [82,83]; and (iii) wettability, i.e., the better wettability of the etchants with PEI than E-BN25 would generate a stronger affinity of etchant for faster diffusion. To illustrate the hydrophobicity, the contact angle of IPA with E-BN25 Fig. 3 Microstructure of the 3D printed multilayer structures. ...
Micropatterned structures have applications in microchips, circuit board designs, microfluidics, evaporator/condenser coils, microelectronics, metasurfaces, and other functional devices. Conventional microfabrication techniques include lithography, vapor deposition, and laser writing. However, these methods have slow processing rates, complex requirements, or costly procedures. As a result, it is challenging to fabricate micropatterned structures onto large-scale surfaces with high production rates and resolution features. Thus, this study focuses on a non-conventional, mask-free micropatterning technique that combines bottom-up 3D printing capable of processing multiple materials and top-down wet etching for selective elimination of sacrificial material. The unique 3D printing, multiphase direct ink writing (MDIW), utilizes various polymer and nanoparticle systems as feedstocks for depositing lamellar structures containing 32–128 sublayers of varying compositions (i.e., wet etchable sacrificial ink and ultraviolet-curable patterning ink). The rapid phase transformation of photosensitive ink (i.e., epoxy and boron nitride (BN)) into solidified features enables “micro-confinement” of the sacrificial ink (i.e., polyethyleneimine). Subsequently, wet etching can locally and selectively dissolve sacrificial polymers by solvent diffusion and polymer dissolution at the polymer–solvent interface. The parameter control (i.e., ink rheology, polymer–polymer interdiffusion, layer multiplication, phase transformation, and solvent-polymer interactions) can precisely tune the lamellar-groove transition, thus forming desirable surfaces or internal microstructures. Microgrooves with a resolution of ≈ 55–170 µm were fabricated by selective wet etching via isopropanol with an etching rate of ≈ 7–11 µg/s. Our hybrid approach, which combines bottom-up 3D printing and top-down wet etching, facilitates surface micropatterning and demonstrates the massive potential of distributing boron nitride nanoparticles for dissipating thermal energies. The micropatterns displayed a thermal conductivity of ≈ 0.2 W/mK for 25wt.% BN with an enhancement of heat dissipation by ≈ 11 °C via confinement of coolants. With production scalability, operation simplicity, and multimaterial compatibility, our 3D-printed micropatterning shows broader applications in nanoparticle assembly, drug delivery, optical lenses, intelligent microbots, and morphing objects.
Graphical Abstract
This technique combines multiphase direct ink writing (MDIW) 3D printing and wet etching capable of micropatterning for thermal management applications.
... Reactive ion etching (RIE) is a very common dry etching strategy, utilizing plasma etch gasses in lithographic procedures. High energy ions are accelerated through electromagnetic fields, colliding to the substrate to break the chemical bonds of the targeted segment [235][236][237][238][239][240][241] . The etch-rate of organic materials is dependent on the number of carbon and oxygen atoms present in the structure [242][243][244][245] . ...
This review article discusses the origins of self-assembly behaviour of linear and non-linear block co- and terpolymers and their application towards the fabrication of high-resolution patterns for nanolithography applications. Comparative analysis for the microphase separation in bulk and thin films is provided, to map the fundamentals of various types of block copolymers (BCPs) inherent properties prior to their use in advanced applications. The opportunities of high-χ/low-N and/or complex architecture co- and terpolymers to self-assemble into nanostrucutres that are beyond the limitations of current lithographic techniques will be presented. The role of molecular characteristics and immiscibility of the blocks on the formation of sub-10 nm or sub-5 nm structures will be discussed. Recent advances in directed self-assembly (or DSA) enable low defect density, extremely minimal dimensions, facile processability, etching selectivity, low-cost and ability to design various patterns. The opportunities of these strategies will be discussed in the context of technological standard requirements and their potential will be evaluated.
... It was already reported that cellulose nanofiber act as a pore forming agent while using water as non solvent. But when methanol is used as non solvent the cellulose nanofiber cannot have any significant effect in the pore formation process because of the lower polarity of methanol (polarity index of water = 10.2, polarity index of methanol = 5.1) (Kleiman et al., 2016). The less water absorption capacity of membrane PCM2 (Methanol) is due to its lesser porosity as compared to PCM2. ...
Petroleum industry wastewater contains high level of crude oil and other types of organic substances that can cause immense harm to the agriculture, aquatic as well as terrestrial organisms. Organic solvent resistance of membranes is very important to treat such wastewater that contains high level of organic pollutants. This work reports the designing of a superhydrophilic and organic solvent resistant nanocomposite membrane using waste bottles made of poly(ethylene terephthalate) (PET) and cellulosic papers. Using in-situ synthesized cellulose nanofibers we could successfully fabricate porous membranes which is not possible for bare PET matrix using water as nonsolvent. Thus, we could successfully replace methanol which was used as a suitable non-solvent in earlier reports by distilled water. We successfully used the membrane for separation of synthetic crude oil-water emulsion. The membrane showed permeability up to 98 Lm⁻²h⁻¹ applying pressure of 1.5 bar. The membrane also achieved removal of more than 97% of organic substances from a crude oil-water emulsion system. The optimum membrane also showed good thermal stability with initial degradation temperature ~350 oC and tensile strength of 0.86 MPa. The antimicrobial property of the nanocomposite membranes could be achieved by coating its surface with carbon dots rooted graphene oxide.
... As isopropyl alcohol has similar polarity with THF (polarity index of 3.9 and 4, respectively [15,16]), it was successful as an alternative solvent for synthesis. It also has a relatively low price compared to the other solvents, thus, can be used in larger quantities for industrial application. ...
Microporous aluminum metal organic framework (Al-MOF) of MIL-68 was synthesized by using low-cost non-carcinogenic solvent isopropanol (IPA) with BET specific surface area measured to be 1698 m²/g. Solvent reusability was also investigated wherein Al-MOFs successfully synthesized using recycled solvent show comparable crystallinity and N2 adsorption with their counterparts synthesized using fresh solvent. The present study achieved 500 times amplification of the original reaction with maintained BET specific surface area. Experimental results show good repeatability and good stability upon exposure to air. To demonstrate its capacity for functional gas adsorption, the synthesized Al-MOF, denoted as MIL-68-IPA, was exposed to high concentrations of acetic acid (AA), wherein it exhibited a capacity of 243.93 ± 27.5 mg/g with a removal rate of 96.6%. At lower concentrations of 100 ppm, it exhibited a removal rate of 100% which shows promising application for removal of AA in the environment.
... In particular, OScA showed a considerably smaller decrease in σ ion than PriA in ACN-based and EA-based solutions, which are more polar than xylene (polar indices of ACN, EA, and xylene are 5.8, 4.4, and 2.5, respectively). 38,39 Unlike typical sulfide SEs that show structural degradation owing to the nucleophilic attack of highly polar solvents, 36,40−42 the OScA material exhibited some resistance to both solvents and binders. This is because the oxysulfide nanolayer formed on the powder surface effectively suppressed the direct chemical reaction between the sulfides and organics, including the solvent and binder. ...
Sulfide solid electrolytes (SEs) with high Li-ion conductivities (σion) and soft mechanical properties have limited applications in wet casting processes for commercial all-solid-state batteries (ASSBs) because of their inherent atmospheric and chemical instabilities. In this study, we fabricated sulfide SEs with a novel core–shell structure via environmental mechanical alloying, while providing sufficient control of the partial pressure of oxygen. This powder possesses notable atmospheric stability and chemical resistance because it is covered with a stable oxysulfide nanolayer that prevents deterioration of the bulk region. The core–shell SEs showed a σion of more than 2.50 mS cm–1 after air exposure (for 30 min) and reaction with slurry chemicals (mixing and drying for 31 min), which was approximately 82.8% of the initial σion. The ASSB cell fabricated through wet casting provided an initial discharge capacity of 125.6 mAh g–1. The core–shell SEs thus exhibited improved powder stability and reliability in the presence of chemicals used in various wet casting processes for commercial ASSBs.
... Samples of iPrSi-doped and native pDCPD ( Fig. 2A) were exposed to an excess of tetrabutylammonium fluoride (TBAF), a low-cost fluoride reagent that selectively cleaves silyl ether functional groups and is often used to etch silicone elastomers (Fig. 2B) (29,30). After 12 hours, the native pDCPD remained fully intact. ...
Thermosets—polymeric materials that adopt a permanent shape upon curing—have a key role in the modern plastics and rubber industries, comprising about 20 per cent of polymeric materials manufactured today, with a worldwide annual production of about 65 million tons1,2. The high density of crosslinks that gives thermosets their useful properties (for example, chemical and thermal resistance and tensile strength) comes at the expense of degradability and recyclability. Here, using the industrial thermoset polydicyclopentadiene as a model system, we show that when a small number of cleavable bonds are selectively installed within the strands of thermosets using a comonomer additive in otherwise traditional curing workflows, the resulting materials can display the same mechanical properties as the native material, but they can undergo triggered, mild degradation to yield soluble, recyclable products of controlled size and functionality. By contrast, installation of cleavable crosslinks, even at much higher loadings, does not produce degradable materials. These findings reveal that optimization of the cleavable bond location can be used as a design principle to achieve controlled thermoset degradation. Moreover, we introduce a class of recyclable thermosets poised for rapid deployment.
... Samples of iPrSi-doped and native pDCPD ( Fig. 2A) were exposed to an excess of tetrabutylammonium fluoride (TBAF), a low-cost fluoride reagent that selectively cleaves silyl ether functional groups and is often used to etch silicone elastomers (Fig. 2B) (29,30). After 12 hours, the native pDCPD remained fully intact. ...
Thermosets play a key role in the modern plastics and rubber industries, comprising ~18% of polymeric materials with a worldwide annual production of 65 million tons. The high density of crosslinks that give these materials their useful properties comes at the expense of facile degradability and re/upcyclability. Here, using the high-performance industrial thermoset plastic poly-dicyclopentadiene (pDCPD) as a model system, we show that when a small number of cleavable bonds are selectively installed within the strands of thermoset plastics using a low-cost comonomer approach, the resulting materials display the same exceptional properties as the native material yet they can undergo triggered degradation to yield soluble, re/upcyclable products of controlled size and functionality. In contrast, installation of cleavable crosslinks, even at comparably high loadings, does not produce degradable materials. These findings shed new light on the topology of polymer networks, revealing cleavable bond location as a universal design principle for controlled thermoset degradation and re/upcycling.<br
