The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
Satoshi Konishi - One of the best experts on this subject based on the ideXlab platform.
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controlling the size of replicable polydimethylsiloxane pdms molds stamps using a stepwise thermal Shrinkage Process
Microelectronic Engineering, 2011Co-Authors: Ok Chan Jeong, Satoshi KonishiAbstract:We demonstrate, for the first time, the size-controllability of replicable three-dimensional polydimethylsiloxane (PDMS) molds/stamps using a stepwise Shrinkage effect in a repeated heat treatment Process. Various microstructures were heated in ambient nitrogen gas to study the temperature effect on the thermal Shrinkage of PDMS. The ramped heat-up and cool-down speeds of the temperature in ambient nitrogen gas were 10^oC/min to various maximum temperatures and 2^oC/min to room temperature, respectively. The three-dimensional shape of the PDMS structure was observed and measured with a scanning laser microscope. The Shrinkage ratios of the PDMS samples heated to 300, 500, and 700^oC were approximately 10%, 13%, and 24%, respectively. There were small variations in Shrinkage, which depended on the micropattern dimensions. The higher temperatures, such as 500 and 700^oC, were not optimum for the sequential replica molding Process, because of locally cracked and bent shapes as well as increased surface roughness. Therefore, we generated and replicated PDMS molds/stamps using a 300^oC multi-step heat treatment Process. During the multi-step heat treatment Process, the microstructures became narrower and deeper, which may have been caused by differences in the thermal capacity within the embossed micropatterns region, the PDMS structure, and the curing Process of the initial PDMS structure. Thus, the structure width decreased as the depth of the samples increased.
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Controlling the size of replicable polydimethylsiloxane (PDMS) molds/stamps using a stepwise thermal Shrinkage Process
Microelectronic Engineering, 2011Co-Authors: Ok Chan Jeong, Satoshi KonishiAbstract:We demonstrate, for the first time, the size-controllability of replicable three-dimensional polydimethylsiloxane (PDMS) molds/stamps using a stepwise Shrinkage effect in a repeated heat treatment Process. Various microstructures were heated in ambient nitrogen gas to study the temperature effect on the thermal Shrinkage of PDMS. The ramped heat-up and cool-down speeds of the temperature in ambient nitrogen gas were 10^oC/min to various maximum temperatures and 2^oC/min to room temperature, respectively. The three-dimensional shape of the PDMS structure was observed and measured with a scanning laser microscope. The Shrinkage ratios of the PDMS samples heated to 300, 500, and 700^oC were approximately 10%, 13%, and 24%, respectively. There were small variations in Shrinkage, which depended on the micropattern dimensions. The higher temperatures, such as 500 and 700^oC, were not optimum for the sequential replica molding Process, because of locally cracked and bent shapes as well as increased surface roughness. Therefore, we generated and replicated PDMS molds/stamps using a 300^oC multi-step heat treatment Process. During the multi-step heat treatment Process, the microstructures became narrower and deeper, which may have been caused by differences in the thermal capacity within the embossed micropatterns region, the PDMS structure, and the curing Process of the initial PDMS structure. Thus, the structure width decreased as the depth of the samples increased.
Ok Chan Jeong - One of the best experts on this subject based on the ideXlab platform.
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controlling the size of replicable polydimethylsiloxane pdms molds stamps using a stepwise thermal Shrinkage Process
Microelectronic Engineering, 2011Co-Authors: Ok Chan Jeong, Satoshi KonishiAbstract:We demonstrate, for the first time, the size-controllability of replicable three-dimensional polydimethylsiloxane (PDMS) molds/stamps using a stepwise Shrinkage effect in a repeated heat treatment Process. Various microstructures were heated in ambient nitrogen gas to study the temperature effect on the thermal Shrinkage of PDMS. The ramped heat-up and cool-down speeds of the temperature in ambient nitrogen gas were 10^oC/min to various maximum temperatures and 2^oC/min to room temperature, respectively. The three-dimensional shape of the PDMS structure was observed and measured with a scanning laser microscope. The Shrinkage ratios of the PDMS samples heated to 300, 500, and 700^oC were approximately 10%, 13%, and 24%, respectively. There were small variations in Shrinkage, which depended on the micropattern dimensions. The higher temperatures, such as 500 and 700^oC, were not optimum for the sequential replica molding Process, because of locally cracked and bent shapes as well as increased surface roughness. Therefore, we generated and replicated PDMS molds/stamps using a 300^oC multi-step heat treatment Process. During the multi-step heat treatment Process, the microstructures became narrower and deeper, which may have been caused by differences in the thermal capacity within the embossed micropatterns region, the PDMS structure, and the curing Process of the initial PDMS structure. Thus, the structure width decreased as the depth of the samples increased.
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Controlling the size of replicable polydimethylsiloxane (PDMS) molds/stamps using a stepwise thermal Shrinkage Process
Microelectronic Engineering, 2011Co-Authors: Ok Chan Jeong, Satoshi KonishiAbstract:We demonstrate, for the first time, the size-controllability of replicable three-dimensional polydimethylsiloxane (PDMS) molds/stamps using a stepwise Shrinkage effect in a repeated heat treatment Process. Various microstructures were heated in ambient nitrogen gas to study the temperature effect on the thermal Shrinkage of PDMS. The ramped heat-up and cool-down speeds of the temperature in ambient nitrogen gas were 10^oC/min to various maximum temperatures and 2^oC/min to room temperature, respectively. The three-dimensional shape of the PDMS structure was observed and measured with a scanning laser microscope. The Shrinkage ratios of the PDMS samples heated to 300, 500, and 700^oC were approximately 10%, 13%, and 24%, respectively. There were small variations in Shrinkage, which depended on the micropattern dimensions. The higher temperatures, such as 500 and 700^oC, were not optimum for the sequential replica molding Process, because of locally cracked and bent shapes as well as increased surface roughness. Therefore, we generated and replicated PDMS molds/stamps using a 300^oC multi-step heat treatment Process. During the multi-step heat treatment Process, the microstructures became narrower and deeper, which may have been caused by differences in the thermal capacity within the embossed micropatterns region, the PDMS structure, and the curing Process of the initial PDMS structure. Thus, the structure width decreased as the depth of the samples increased.
Wantai Yang - One of the best experts on this subject based on the ideXlab platform.
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Volume Shrinkage of UV-curable coating formulation investigated by real-time laser reflection method
Journal of Coatings Technology Research, 2013Co-Authors: Yu Jian, Tongzhou Jiang, Wantai Yang, Chunguang Li, Yong He, Jun NieAbstract:Volume Shrinkage is one of the main drawbacks of UV-cured coatings and can lead to premature coating failures. Due to the rapid polymerization during UV-curing, real-time volume Shrinkage has been challenging to measure accurately. In this article, the Shrinkage Process of UV-curable formulations was systematically investigated by a recently developed laser reflection method. The influence of oligomers, monomers, and photoinitiators on Shrinkage Process has been evaluated. Compared with the oligomers, the monomer was the main contributor to Shrinkage due to the high concentration of double bonds. Polymerization Shrinkage could be reduced by increasing the oligomer/monomer ratio. Because monomers were the main contributors of Shrinkage, the chemical structure of monomers was important for decreasing Shrinkage. Methacrylate monomers decreased the final Shrinkage but unfortunately reduced the conversion. Monomers with a high degree of ethoxylation lowered the Shrinkage and simultaneously increased the conversion. The concentration of photoinitiators had no obvious effect on the normalized Shrinkage. Thus, the low Shrinkage caused by the low concentration of photoinitiators was only attributed to the significant drop of the conversion. © 2012 American Coatings Association & Oil and Colour Chemists' Association.
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Volume Shrinkage of UV-curable coating formulation investigated by real-time laser reflection method
Journal of Coatings Technology and Research, 2012Co-Authors: Yu Jian, Tongzhou Jiang, Chunguang Li, Yong He, Wantai YangAbstract:Volume Shrinkage is one of the main drawbacks of UV-cured coatings and can lead to premature coating failures. Due to the rapid polymerization during UV-curing, real-time volume Shrinkage has been challenging to measure accurately. In this article, the Shrinkage Process of UV-curable formulations was systematically investigated by a recently developed laser reflection method. The influence of oligomers, monomers, and photoinitiators on Shrinkage Process has been evaluated. Compared with the oligomers, the monomer was the main contributor to Shrinkage due to the high concentration of double bonds. Polymerization Shrinkage could be reduced by increasing the oligomer/monomer ratio. Because monomers were the main contributors of Shrinkage, the chemical structure of monomers was important for decreasing Shrinkage. Methacrylate monomers decreased the final Shrinkage but unfortunately reduced the conversion. Monomers with a high degree of ethoxylation lowered the Shrinkage and simultaneously increased the conversion. The concentration of photoinitiators had no obvious effect on the normalized Shrinkage. Thus, the low Shrinkage caused by the low concentration of photoinitiators was only attributed to the significant drop of the conversion.
Yu Jian - One of the best experts on this subject based on the ideXlab platform.
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Volume Shrinkage of UV-curable coating formulation investigated by real-time laser reflection method
Journal of Coatings Technology Research, 2013Co-Authors: Yu Jian, Tongzhou Jiang, Wantai Yang, Chunguang Li, Yong He, Jun NieAbstract:Volume Shrinkage is one of the main drawbacks of UV-cured coatings and can lead to premature coating failures. Due to the rapid polymerization during UV-curing, real-time volume Shrinkage has been challenging to measure accurately. In this article, the Shrinkage Process of UV-curable formulations was systematically investigated by a recently developed laser reflection method. The influence of oligomers, monomers, and photoinitiators on Shrinkage Process has been evaluated. Compared with the oligomers, the monomer was the main contributor to Shrinkage due to the high concentration of double bonds. Polymerization Shrinkage could be reduced by increasing the oligomer/monomer ratio. Because monomers were the main contributors of Shrinkage, the chemical structure of monomers was important for decreasing Shrinkage. Methacrylate monomers decreased the final Shrinkage but unfortunately reduced the conversion. Monomers with a high degree of ethoxylation lowered the Shrinkage and simultaneously increased the conversion. The concentration of photoinitiators had no obvious effect on the normalized Shrinkage. Thus, the low Shrinkage caused by the low concentration of photoinitiators was only attributed to the significant drop of the conversion. © 2012 American Coatings Association & Oil and Colour Chemists' Association.
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Volume Shrinkage of UV-curable coating formulation investigated by real-time laser reflection method
Journal of Coatings Technology and Research, 2012Co-Authors: Yu Jian, Tongzhou Jiang, Chunguang Li, Yong He, Wantai YangAbstract:Volume Shrinkage is one of the main drawbacks of UV-cured coatings and can lead to premature coating failures. Due to the rapid polymerization during UV-curing, real-time volume Shrinkage has been challenging to measure accurately. In this article, the Shrinkage Process of UV-curable formulations was systematically investigated by a recently developed laser reflection method. The influence of oligomers, monomers, and photoinitiators on Shrinkage Process has been evaluated. Compared with the oligomers, the monomer was the main contributor to Shrinkage due to the high concentration of double bonds. Polymerization Shrinkage could be reduced by increasing the oligomer/monomer ratio. Because monomers were the main contributors of Shrinkage, the chemical structure of monomers was important for decreasing Shrinkage. Methacrylate monomers decreased the final Shrinkage but unfortunately reduced the conversion. Monomers with a high degree of ethoxylation lowered the Shrinkage and simultaneously increased the conversion. The concentration of photoinitiators had no obvious effect on the normalized Shrinkage. Thus, the low Shrinkage caused by the low concentration of photoinitiators was only attributed to the significant drop of the conversion.
Jerry Y. H. Fuh - One of the best experts on this subject based on the ideXlab platform.
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High resolution UV roll-to-roll nanoimprinting of resin moulds and subsequent replication via thermal nanoimprint lithography
Nanotechnology, 2012Co-Authors: Jarrett J. Dumond, Kambiz Ansari Mahabadi, Yew Sok Yee, Christina Tan, Heow Pueh Lee, Jerry Y. H. Fuh, Hong Yee LowAbstract:UV roll-to-roll nanoimprinting at high resolution is still a relatively unexplored field of study with far-reaching application potential. One enabling technology that is particularly worthy of attention is mass production of high resolution resin moulds via UV roll-to-roll nanoimprinting at such high throughput and low cost that they can be used only once and disposed of or recycled economically. Low cost, high resolution resin moulds can greatly improve the production cost profile for a number of applications in biomedicine, nanofluidics, data storage and electronics with relatively low unit values but which require one or more nanoscale lithography steps. In this report, UV roll-to-roll nanoimprinting was employed to fabricate high fidelity resin moulds with nanoscale as well as mixed micro- and nanoscale features down to 50 nm feature diameter, at up to 120 cm(2) area and at 10 m min(-1) throughput. UV roll-to-roll nanoimprinted resin moulds were subsequently segmented out, employed in a batch mode thermal nanoimprinting Process, and characterized to study performance and demonstrate viability. The results show that high resolution mixed nanostructures can be faithfully replicated in PMMA on silicon substrates with minimal volumetric Shrinkage. Process details and challenges specific to roll-to-roll fabrication of resin moulds are discussed at length, particularly with respect to the curvature uniformity of the imprint roller.
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Post-cure Shrinkage of photo-sensitive material used in laser lithography Process
Journal of Materials Processing Technology, 1997Co-Authors: Jerry Y. H. Fuh, Y. S. Chooo, Y.-s. Wong, L Lu, T. Miyazawa, Andrew Y. C. Nee, W L Wang, S. H. HoAbstract:Shrinkage causes distortion and warpage due to the internal stresses built up during fabrication, and greatly influences the dimensional accuracy of a part. This paper presents an experimental study on the relationships between the key parameters of the laser lithography (LL) (or commonly known as Stereolithography) Process and the resulting post-curing Shrinkage due to thermal and ultraviolet (UV) exposure. The UV-sensitive material used in the experiment is an acrylic-based resin, namely SCR-310. The post-curing Process causes partially-cured and uncured resin to be further polymerised and is necessary for the improvement of the final mechanical properties of the parts. In principle, a larger laser power or a smaller layer pitch will result in a smaller amount of partially-cured or uncured resin, with less Shrinkage after post-curing. A better understanding of the behaviour and characterisation of the Shrinkage Process during thermal and UV treatments will help to reduce the post-cure distortion, and will lead to more accurate rapid prototypes produced by the LL Process. The origin of Shrinkage from photo-polymerisation is closely examined through the measurements along both the scanning and transversal directions.