Abstract:Nanoparticles and polymers have great potential for lowering cost and increasing functionality of printed sensors and electronics. However, creation of practical devices requires that many of these materials be patterned on a single substrate, and many current patterning processes can only handle a single material at a time, necessitating alignment of serial processing steps. Higher throughput and lower cost can be achieved by patterning multiple materials simultaneously. To this end, the microfluidic molding … Show more
“…To solve the abovementioned problems, several solvent-permeable molds have been previously reported. [15][16][17][18][19][20] In our studies on the design of lithography materials derived from biomass, solvent-permeable molds www.advancedsciencenews.com www.mme-journal.de peeling induced by demolding during the nanoimprint lithography processes. The adhesion underlayer material of novolac derivatives has been developed and reported.…”
and resist materials were investigated for the expanded nanoimprint lithography and application of biomass resources. [21][22][23][24][25] Herein, high-accuracy nanopatterning of PES using dimethylformamide as a dilution solvent was obtained by direct thermal nano imprint lithography using the newly modified solvent-permeable cellulosebased mold.In summary, the 900-nm line pattern failure of PES containing dimethylformamide as a dilution solvent was solved using the solvent-permeable cellulosebased mold. The direct nanoimprint lithography using the new solvent-permeable mold and solvent-mixed super-engineering plastics has realized the surface nanostructures of PES.
Experimental SectionThe structures of a) hydroxypropyl cellulose with thermally cross-linked acryloyloxyalkyl groups in the solvent-permeable cellulose-based mold, b) 2-hydroxy-2-methylpropiophenone as an ultraviolet(UV) initiator, c) azobisisobutyronitrile as a thermal initiator, d) polyethersulfone, e) dimethylformamide as a dilution solvent with high solubility for increasing the fluidity of PES, f) novolac derivatives with hydroxyl groups to react with the cross-linker to improve adhesion to polyethersulfone during the imprinting process, g) 1,3,4,6-tetrakis(methoxymethyl) glycoluril as a cross-linker, and h) pyridinium p-toluenesulfonate as an initiator are shown in Figure 1.2-Methacryloyloxyalkyl isocyanate was reacted with hydroxypropyl cellulose to add thermally cross-linked acryloyloxyalkyl groups into the hydroxypropyl cellulose to prepare the solvent-permeable cellulose-based mold. The resulting chemical reaction between 2-methacryloyloxyalkyl isocyanates and hydroxypropyl cellulose was evaluated using attenuated total reflectance Fourier transform infrared spectroscopy. [26][27][28] Methyl ethyl ketone was blended with 2-methacryloyloxyalkyl isocyanates and hydroxypropyl cellulose. The content of 2-methacryloyloxyalkyl isocyanate and hydroxypropyl cellulose in the solution was 26 wt%. The solution was stirred under a nitrogen atmosphere at 63 °C for 2.5 h, after adding triethylamine with a concentration of 7.9 wt% to the solution. Gel-permeation chromatography (HLC-8320GPC, Tosoh) was used to obtain the molecular weight of solvent-permeable cellulosebased mold. The solvent-permeable cellulose-based mold with an average molecular weight of 53 000 relative to a polystyrene standard was developed. The solvent-permeable cellulose-based mold with thermally cross-linked acryloyloxyalkyl groups was formulated with the following concentrations: 95 wt% of cellulose derivative, 2.5 wt% of 2-hydroxy-2-methylpropiophenone, and 2.5 wt% of azobisisobutyronitrile as a thermal initiator.The adhesion underlayer material on substrates, such as stainless mesh plate and silicon wafer was prepared to provide an adhesion between the substrates and patterning materials, such as PES and solvent-permeable cellulose-based mold, thereby reducing the pattern Polyethersulfone (PES) with a glass transition temperature of 224 °C is a class of high-performance super engi...
“…To solve the abovementioned problems, several solvent-permeable molds have been previously reported. [15][16][17][18][19][20] In our studies on the design of lithography materials derived from biomass, solvent-permeable molds www.advancedsciencenews.com www.mme-journal.de peeling induced by demolding during the nanoimprint lithography processes. The adhesion underlayer material of novolac derivatives has been developed and reported.…”
and resist materials were investigated for the expanded nanoimprint lithography and application of biomass resources. [21][22][23][24][25] Herein, high-accuracy nanopatterning of PES using dimethylformamide as a dilution solvent was obtained by direct thermal nano imprint lithography using the newly modified solvent-permeable cellulosebased mold.In summary, the 900-nm line pattern failure of PES containing dimethylformamide as a dilution solvent was solved using the solvent-permeable cellulosebased mold. The direct nanoimprint lithography using the new solvent-permeable mold and solvent-mixed super-engineering plastics has realized the surface nanostructures of PES.
Experimental SectionThe structures of a) hydroxypropyl cellulose with thermally cross-linked acryloyloxyalkyl groups in the solvent-permeable cellulose-based mold, b) 2-hydroxy-2-methylpropiophenone as an ultraviolet(UV) initiator, c) azobisisobutyronitrile as a thermal initiator, d) polyethersulfone, e) dimethylformamide as a dilution solvent with high solubility for increasing the fluidity of PES, f) novolac derivatives with hydroxyl groups to react with the cross-linker to improve adhesion to polyethersulfone during the imprinting process, g) 1,3,4,6-tetrakis(methoxymethyl) glycoluril as a cross-linker, and h) pyridinium p-toluenesulfonate as an initiator are shown in Figure 1.2-Methacryloyloxyalkyl isocyanate was reacted with hydroxypropyl cellulose to add thermally cross-linked acryloyloxyalkyl groups into the hydroxypropyl cellulose to prepare the solvent-permeable cellulose-based mold. The resulting chemical reaction between 2-methacryloyloxyalkyl isocyanates and hydroxypropyl cellulose was evaluated using attenuated total reflectance Fourier transform infrared spectroscopy. [26][27][28] Methyl ethyl ketone was blended with 2-methacryloyloxyalkyl isocyanates and hydroxypropyl cellulose. The content of 2-methacryloyloxyalkyl isocyanate and hydroxypropyl cellulose in the solution was 26 wt%. The solution was stirred under a nitrogen atmosphere at 63 °C for 2.5 h, after adding triethylamine with a concentration of 7.9 wt% to the solution. Gel-permeation chromatography (HLC-8320GPC, Tosoh) was used to obtain the molecular weight of solvent-permeable cellulosebased mold. The solvent-permeable cellulose-based mold with an average molecular weight of 53 000 relative to a polystyrene standard was developed. The solvent-permeable cellulose-based mold with thermally cross-linked acryloyloxyalkyl groups was formulated with the following concentrations: 95 wt% of cellulose derivative, 2.5 wt% of 2-hydroxy-2-methylpropiophenone, and 2.5 wt% of azobisisobutyronitrile as a thermal initiator.The adhesion underlayer material on substrates, such as stainless mesh plate and silicon wafer was prepared to provide an adhesion between the substrates and patterning materials, such as PES and solvent-permeable cellulose-based mold, thereby reducing the pattern Polyethersulfone (PES) with a glass transition temperature of 224 °C is a class of high-performance super engi...
“…Over the past few years, we investigated in depth these mechanisms, mainly for aqueous dispersions of nanoparticles 23 and demonstrated successful fabrications of nanoparticle-dense assemblies, with applications ranging from optical metamaterials 24 to surface-enhanced Raman spectroscopy substrates 25 . Demko et al 26,27 also reported similar works and extended the pervaporation technique to the use of non-aqueous dispersions, using the development of a solvent-compatible permeable matrix.Fig. 1Fabrication process flow of multilayer polymer micro-structures. a (Left) Reversible sealing of dead-end channels embedded in a PDMS mold by a PDMS membrane.…”
Section: Introductionmentioning
confidence: 92%
“…These phenomena result from a subtle coupling between the build-up of mechanical stresses during solidification, mechanical deformations of the PDMS matrix, and adhesion between the composite and the PDMS walls. Demko et al 26,27 showed that the use of a more rigid, but still permeable, matrix allows to minimize such deformations.…”
In view of the extensive increase of flexible devices and wearable electronics, the development of polymer micro-electro-mechanical systems (MEMS) is becoming more and more important since their potential to meet the multiple needs for sensing applications in flexible electronics is now clearly established. Nevertheless, polymer micromachining for MEMS applications is not yet as mature as its silicon counterpart, and innovative microfabrication techniques are still expected. We show in the present work an emerging and versatile microfabrication method to produce arbitrary organic, spatially resolved
multilayer
micro-structures, starting from dilute inks, and with possibly a large choice of materials. This approach consists in extending classical microfluidic pervaporation combined with MIcro-Molding In Capillaries. To illustrate the potential of this technique, bilayer polymer double-clamped resonators with integrated piezoresistive readout have been fabricated, characterized, and applied to humidity sensing. The present work opens new opportunities for the conception and integration of polymers in MEMS.
“…Permeable templates of gases and solvents have also been reported to solve air trapping and template damage caused by gases such as nitrogen and oxygen generated from microimprinted materials . Volatile solvents produced from the formulation of such materials, as well as gases such as nitrogen and oxygen generated from them that are involved in the cross‐linked reactions, cause incomplete filling of the cross‐linked liquid materials in the template during the UV or thermal curing processes.…”
Section: Introductionmentioning
confidence: 99%
“…Permeable templates of gases and solvents have also been reported to solve air trapping and template damage caused by gases such as nitrogen and oxygen generated from microimprinted materials. [7][8][9][10] Volatile solvents produced from the formulation of such materials, as well as gases such as nitrogen and oxygen generated from them that are involved in the cross-linked reactions, cause incomplete fi lling of the cross-linked liquid materials in the template during the UV or thermal curing processes. The use of volatile solvents with high coating property and solubility into the microimprinted materials, such as the conventionally used compounds, plastic resins, and imprinted materials, has been limited in mold injection and imprint lithography.…”
A gas‐permeable cellulose template for microimprint lithography has been synthesized and characterized for the reduction of template damage and gas trapping caused by solvents and oxygen generated from cross‐linked materials. The 5 μm line‐pattern failure of the microimprinted UV cross‐linked liquid materials with 4.7 wt% acetone as a volatile solvent is solved by using the gas‐permeable cellulose template because of its increased oxygen permeability. The gas‐permeable cellulose template also allows the use of volatile solvents with high coating property and solubility into the microimprinted materials instead of the compounds and plastic resins conventionally used in mold injection.
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