The Outstanding Achievement Award
The Photopolymer Science and Technology Award No.181100
Tokyo University of Science
The Photopolymer Science and Technology Award No. 181100, the Outstanding Achievement Award 2018, was presented to Susumu Fujimori (Tokyo University of Science) for his outstanding achievements in photopolymer science and technology, “The Invention of Molded Mask Method, A Pioneering Technology of Nanoimprint Lithography”.
Professor Susumu Fujimori is currently an assistant professor at Tokyo University of Science. His research interest has been micro-nano-fabrication techniques based on the molding lithography for optical and semiconductor components. He worked at NTT Advanced Technology Corporation from 2001 to 2015, and Nippon Telegraph and Telephone Public Corporation from 1975 to 2001.
Nanoimprint lithography is one of the promising technologies to fabricate fine structures cost-effectively. Over the past decades, a variety of fine pattern fabrication technologies based on beam processing, such as optical, laser, electron, and ion beam, have been developed to improve a critical resolution. The beam processing has been indispensable for the mass production of integrated semiconductor circuits and optical components.
However, further developments required tremendous efforts and funding to overcome both scientific and economic problems. About 20 years ago, nanoimprint lithography using stamping technology attracted the attention as a new method to overcome the issues and even the sub-10nm lithography was demonstrated in 1995. The nanoimprint lithography is now approaching next generation’s ultra-large-scaled-integrated (ULSI) circuit lithography.
On the other hand, Prof. Susumu Fujimori presented the technology named ‘molded mask method’ to replicate fine patterns on a mold to a polymer material in the 1970’s. He showed that fine patterns could be replicated to thermal and UV resins on semiconductor substrate, which is the origin of the nanoimprint lithography. He firstly demonstrated the replication of submicron patterns based on the molding method and fabricated fine optical elements. These methods were classical approach, but everyone never thought the methods were applicable for submicron pattering. His method was outstanding and innovative at that time.
He obtained the patent in 1979, which must be the origin of so-called UV nanoimprint. He proposed the new fabrication method using UV curable resin, such as photoresist coated on the substrate. The resin film is pressed by a patterned UV transparent mold, and then cured by UV exposure through the mold. Subsequently the pattern on the cured resin film is engraved and replicated onto an underlying semiconductor surface by dry etching. This method was so-called ‘molded mask method’. He demonstrated the replication of submicron-scaled-grating patterns by the molded mask method, which is just the same as so-called “UV-nanoimprint lithography” .
He also proposed a hot-pressing process to thermal resin film on the substrate, which is a precedent technology of the thermal nanoimprint lithography .
He published several reports and review articles [2-4]. One of them was the invited-review paper for the Journal of Photopolymer Science and Technology .
Now, the molding method so-called nanoimprint lithography is being applied for several industrial field such as sub-wavelength-optical elements for cost effective mass production and also approaching toward next generation’s advanced-semiconductor-device fabrication for superior resolution.
He is a pioneer of the molding method for the micro-nano patterning on the resist polymer, namely nanoimprint lithography.
His work was far ahead of its time and the contribution and originality are outstanding. With these achievements, the Outstanding Achievement Award 2018 was presented to Prof. Susumu Fujimori.
1. S. Fujimori and M. Kondo, “Method of mask fabrication”, Japan Patent 947244 (applied in 1975 and registered in 1979), Japan Patent Office.
2. M. Kondo and S. Fujimori, “A micro fabrication method with a molded mask”, IEICE Technical report, CPM76-125 (1977) 29 [in Japanese].
3. S. Fujimori, “Fine pattern fabrication by the molded mask method (Nanoimprint lithography) in the 1970s,” Jpn. J. Appl. Phys., 48 (2009) 849.
4. S. Fujimori, “The molded mask method: The origin of nanoimprint lithography,” J. Photopolym. Sci. Technol., 29 (2016) 849.
Osaka Prefecture University
The Best Paper Award 2018
The Photopolymer Science and Technology Award 182100
Yusuf Yagci, Gorkem Yilmaz, and Mustafa Ciftci
Istanbul Technical University, Republic of Turkey
The Photopolymer Science and Technology Award No. 182100, the Best Paper Award 2018, was presented to Yusuf Yagci, Gorkem Yilmaz and Mustafa Ciftci (Istanbul Technical University, Republic of Turkey) for their outstanding contribution published in Journal of Photopolymer Science and Technology, 30, (2017) 385–392, entitled “Photoinitiated Metal Free Living Radical and Cationic Polymerizations”.
The application of photochemical approaches to synthetic polymer chemistry has become an attractive research domain as it congregates a wide range of economic and ecological anticipations, and offers several advantages compared to the other synthetic methodologies [1,2]. Various macromolecular structrures including branched polymers , hydrogels , cryogels, as well as metal and clay nanocomposites  can be used. Photoinitiated polymerizations usually proceed in a chain process that is initiated by light and both the initiating species and the growing chain ends are radicals or cations. However, conventional photochemical procedures suffer from the inevitable transfer and termination reactions, which prevents the syntheses of polymers with well-defined structures and molecular weight characteristics. Recent developments in photomediated living/controlled radical and cationic polymerization made it possible to prepare various well-defined polymers with complex architecture under mild conditions . Among the most recent developments, the realization of controlled living polymerization processes under metal-free conditions receive a great attention as reflected by the numbers of papers and citations on the topic. Recently, Yagci and coworkers have developed several strategies eliminating the use of such additives in photoinduced controlled/living radical and cationic polymerizations. Thus, they have reported examples of metal free atom transfer radical polymerization (ATRP), cationic polymerizations and combination of these two processes for the preparation of block copolymers from structurally different monomers.
In the case of metal free photo ATRP, polynuclear aromatic hydrocarbons, certain aromatic carbonyl compounds and dyes were shown to be efficient photosensitizers acting in UV and visible range depending on their absorption characteristics . The excited states of these compounds undergo photoinduced electron transfer reaction with appropriate alkyl halides through oxidative or reductive quenching mechanisms leading to the formation of polymers with narrow molecular weight distribution and controlled chain-end functionality. These photoredox systems offer new possibilities for not only control over the polymerization but also surface modification, spatiotemporal control and network formations by using suitably selected monomers for specific applications under metal free conditions. Additionally, in another study they have showed that metal-free ATRP can be combined with the metal-free ring opening polymerization (ROP) strategy to obtain block copolymers in a one-shot manner .
The metal free approach was not limited to ATRP and ROP. Yagci group developed a new photoinitiating system for living cationic polymerization of vinyl ethers by using Mn2(CO)10 in the absence of metals or Lewis acids . In the described approach, visible-light irradiation of Mn2(CO)10 in the presence of an alkyl bromide resulted in the formation of carbon-centered radicals. The photochemically generated radicals were then oxidized by diphenyliodonium ions to the corresponding cations. These cations could add vinyl ether monomers, which were then rapidly deactivated by the bromide anions to give α-halide functional end groups. Poly(vinyl ether) chains were then grown through successive photoinduced radical oxidation/addition/ deactivation (PROAD) in a controlled manner. The living nature of the system was evaluated through kinetics studies and block copolymer formation. The described process is believed to lead to new possibilities for the preparation of complex macromolecular structures and surface grafts.
As described above, the authors have extensively contributed to the development of new light induced metal free systems for the preparation of various macromolecular architectures. These motivating research outcomes were presented at the Annual Conference of Photopolymer Science and Technology in 2017, and summarized in the Journal of Photopolymer Science and Technology (JPST) .
1. Y. Yagci, S. Jockusch, N. J. Turro, Macromolecules, 43 (2010) 6245-6260.
2. G. Yilmaz, Y. Yagci, J. Photopolym. Sci. Technol., 29 (2016) 91-98.
3. a) S. Bektas, M. Ciftci, Y. Yagci, Macromolecules, 46, (2013) 6751-6757; b) M. Ciftci, M. U. Kahveci, Y. Yagci, X. Allonas, C. Ley, H. Tar, Chem. Commun., 48 (2012) 10252-10254.
4. E. Murtezi, M. Ciftci, Y. Yagci, Polym. Int., 64 (2015) 588-594.
5. Y. Yoshikawa, M. Ciftci, M. Aydin, M. Narusawa, T. Karatsu, Y. Yagci, J. Photopolym. Sci. Technol., 28 (2015) 769-774.
6. S. Dadashi-Silab, S. Doran, Y. Yagci, Chem. Rev., 116 (2016) 10212-10275.
7. a) A. Allushi, S. Jockusch, G. Yilmaz, Y. Yagci, Macromolecules, 49, (2016) 7785-7792; b) C. Kutahya, F. S. Aykac, G. Yilmaz, Y. Yagci, Polym. Chem., 7 (2016) 6094-6098; c) X. Liu, L. Zhang, Z. Cheng, X. Zhu, Polym. Chem., 7, (2016) 689-700; d) A. Allushi, C. Kutahya, C. Aydogan, J. Kreutzer, G. Yilmaz, Y. Yagci, Polym. Chem., 8 (2017) 1972-1977.
8. C. Aydogan, C. Kutahya, A. Allushi, G. Yilmaz, Y. Yagci, Polym. Chem., 8 (2017) 2899-2903.
9. M. Ciftci, Y. Yoshikawa, Y. Yagci, Angew. Chem. Int. Ed., 56 (2017) 519-523.
10. M. Ciftci, G. Yilmaz, Y. Yagci, J. Photopolym. Sci. Technol., 30 (2017) 385-392.
The Best Paper Award 2018
The Photopolymer Science and Technology Award 182200
Chen-Gang Wang, Feifei Li, and Atsushi Goto
Nanyang Technological University, Singapore
The Photopolymer Science and Technology Award No. 182200, the Best Paper Award 2018, was presented to Chen-Gang Wang, Feifei Li, and Atsushi Goto (Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University) for their outstanding contribution published in Journal of Photopolymer Science and Technology, 30, (2017) 379–383, entitled “Photo-Controlled Organocatalyzed Living Radical Polymerization and Its Application to Polymer Brush Synthesis on Surface”.
Living radical polymerization (LRP) is a useful technique for tailoring polymer structures with predictable molecular weights and narrow molecular weight distributions [1,2]. In addition to thermal heating, photo irradiation has extensively been utilized to control LRP [3-22]. The photo reactions do not require heat and are therefore applicable to functional groups and materials that decompose at high temperatures. A photochemical stimulus is one of the most useful external stimuli that can instantly switch the reactions “on” and “off” at desired timings and can spatially trigger the reactions at specific positions and spaces. The reactions are also selectively inducible in response to the irradiation wavelengths; hence, multiple reactions may be regulated in one pot by simply altering the irradiation wavelength. Because of these advantages, photo-controlled LRP has opened up new intriguing applications.
This paper reports a new family of photo-controlled LRP that the authors have recently developed. The polymerization uses alkyl iodides as initiators and organic molecules as catalysts, which is the first photo-controlled LRP for the use of organic catalysts [23,24]. This polymerization is an ideal on-off switchable system by an external photo stimulus and that the polymerization speed is also finely tunable by the photo irradiation power. A unique aspect is that various organic catalysts with different absorption wavelengths can be utilized, namely, the polymerization can be selectively controlled at desired wavelengths by exploiting appropriate catalysts. The feasible wavelength ranges from 350 nm to 750 nm, covering the whole visible region. This polymerization is compatible with various functional monomers, and their block copolymers are obtainable. An advantage of this system is that no special initiators or metals are used; in addition, the catalysts are commercially available. The facile operation, fine response to wavelength, and applicability to a wide range of polymer designs may be greatly beneficial in various applications. A useful application demonstrated in this paper is the synthesis of polymer brushes on surfaces. The photo polymerization was applied to surface-initiated polymerization, successfully providing concentrated polymer brushes with high surface occupancies and also patterned polymer brushes with the use of photo-masks.
These results were also presented at the International Conference of Photopolymer Science and Technology in 2017. The work on the patterned polymer brushes has recently greatly progressed, providing novel structures of patterned polymer brushes. This progress will be presented at the International Conference of Photopolymer Science and Technology in 2018 . The results presented in this paper provide a new useful family of photo-controlled LRP with unprecedented advantages, and hence deserves the Photopolymer Science and Technology Award.
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3. For reviews on photo-controlled LRP, see refs 3-5. S. Yamago and Y. Nakamura, Polymer, 54 (2013) 981.
4. X. Pan, M. A. Tasdelen, J. Laun, T. Junkers, Y. Yagci, and K. Matyjaszewski, Prog. Polym. Sci., 62 (2016) 73.
5. C. Chen, M. Zhong, and J. A. Johnson, Chem. Rev., 116 (2016) 10167.
6. A. Goto, J. C. Scaiano, and L. Maretti, Photochem. Photobiol. Sci., 6 (2007) 833.
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25. C. G. Wang, C. Chen, and A. Goto, to be submitted.
Haruyuki Okamura, Osaka Prefecture University