This feature issue of Optical Materials Express contains selected papers presented at the 14th International Conference on Frontiers of Polymers and Advanced Materials 2016 (ICFPAM 2016) held in Daejeon, South Korea, October 31 - November 4, 2016. The conference was organized by Hannam University commemorating the 60th anniversary of its foundation. The ICFPAM 2016 was a sequel to very successful series of international meetings organized in different locations around the world. These ICFPAM series of conferences have facilitated the coming together of scientists, engineers and business leaders to discuss multidisciplinary aspects of material science including polymers over the years. Attendees at the ICFPAM 2016 included Prof. Akira Suzuki (Nobel Laureate in Chemistry 2010, Hokkaido University, Japan), Prof. Paras N. Prasad (University at Buffalo, SUNY, USA), Prof. Jürgen Rühe (University of Freiburg, Germany), Prof. Kilwon Cho (POSTECH, Korea) in addition to distinguished scientists as 32 keynote speakers and 148 invited speakers. We also had 110 contributed and poster presentations. The total number of participants was over 400 coming from 36 countries covering almost all continents (Fig. 1). All major topics of current and prospective interest in polymer science, advanced materials and technologies and their practical applications, broadly covered in the ICFPAM 2016 conference with these being themes.

 

Fig. 1 View of the Plenary Lecture by Prof. Akira Suzuki (Nobel Laureate in Chemistry 2010, Hokkaido Uni.) at the ICFPAM 2016 (Daejeon Convention Center, S. Korea).

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The selected presentations of ICFPAM 2016 are being published as a special issue in Optical Materials Express. The articles presented here cover a wide range of subject and collected under the theme of “organic and polymeric materials for photonics”. The topics covered in this issue contain an interesting mix of fundamental science, material engineering, and applications representing a cross section of interests presented during the conference.

Chirality is a prominent force in natural materials, governing cell based communication and regulation. Chirality plays a crucial role in biological phenomena ranging from senses like taste and smell to activity of pharmaceutical. The role of chirality in photonic materials has only recently been explored. In an in depth review in this issue Prasad et. al. look at chiro-optical properties of chiral polymers [1]. The review covers the multiscale modelling of such polymers as well as their optical and magneto-optical properties. It delves into the relevance and role of supramolecular organization in such effects. This timely review of chiral polymers also discusses the potential applications of such structures.

On the topic of nanomaterials, Onodera and associates discuss the convective assembly of thin films of highly-orientated polydiacetylene nanofibers. The oriented films were seen to exhibit high third-order nonlinear optical susceptibility [2]. Miura and associates describe the photoreduction of a gold ion-dendrimer complex to generate Au clusters, embedded in a dendrimer nanoparticle [3]. This paper also describes the effect of temporal variation of UV irradiation on cluster sizes. Ali and associates have studied the synthesis and photocatalytic activities of graphene oxide-TiO₂ (GO-TiO₂) nanotubes [4]. They investigated the effect of synthesis routes on the photocatalytic activity of GO-TiO₂ nanohybrid. The graphene oxide modified nanotubes were found to offer superior photocatalytic activity compared to pristine TiO₂ nanotubes. Park et. al. report the synthesis and characterization of vinyl-terminated cadmium free quantum dots. Such materials can have many interesting properties due to easy chemical interaction between the double bond of the functionalized ligand and other chemical groups through photopolymerization or thiol-ene reaction. The authors also showed the facile introduction of quantum dots into polymeric microstructures [5].

There are three papers dealing with electro-optical materials and devices in this feature issue, Kim and associates study the potential of a combination of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and silver nanoparticle wires as a composite electrode material [6]. They show that the nanocomposite material is highly compatible to photolithography, and allows easy transfer of patterned structures. Han et. al. explore programmable dual electrochromic device using based on a polymer consisting of tri-EDOT and azine group. This paper explores the mechanism underlying electrochromism in the devices as well its efficiency [7]. Luo et. al. present their findings on efficient contact poling of guest-host electro-optic (EO) polymer thin films over large areas on soda-lime glass [8]. They demonstrate the potential of such a technique to produce films with large second-order nonlinear susceptibilities and Pockels coefficients. Tunable electro-optical properties of U-shaped-alignment (USA) in-plane switching (IPS) liquid crystal (LC) devices were studied by Lin and associates [9].

In the 3D fabrication category this issue contains the report of a facile protocol for 3D fabrication of advanced hybrid composite of carbon nanotubes (CNTs) and Ruthenium (Ru) inverse opal by Jang and colleagues [10]. In another paper Ramirez and associates present the direct writing of low-loss waveguides using 405 nm light. They demonstrate a scalable and cheap fabrication of high quality grating [11]. Liu and associates review the large area fabrication of biomimetic hierarchical structures by femtosecond direct writing and multi-exposure lithography [12]. The refractive index of common photoresists used for femtosecond direct writing has been determined by Gissbl and colleagues [13]. This would be a good reference for the fabrication of photonic structures with required gradients in refractive index.

This special issue contains three papers discussing the broad topic of solar cells. Lee et. al. discuss the derivatization of reduced graphene oxide with fullerenol derivatives to increase their processability. The potential of such materials as hole transport layers in organic solar cells is also discussed [14]. Wen et. al. demonstrates the fabrication of ITO-free flexible polymer solar cells in the second paper in this category [15]. The synthesis and application of gel polymer electrolytes (GPEs) based on poly(ethylene oxide) (PEO) and phthaloyl chitosan (PhCh) in dye-sensitized solar cells (DSSCs) is reported by Shah et. al. [16].

Plasmonic materials and devices are represented by three articles in this issue. Haffner and associates report plasmonic electro-optical modulators operating at the vicinity of the absorption resonance of the electro-optical material [17]. This work compares the near-resonance operation to the prominent trend of off-resonance photonics demonstrating reduction in voltage-length product and loss. Top-emitting organic light-emitting devices (TOLEDs) reported by Jin et.al. couples surface plasmon–polariton (SPP) and microcavity modes in a corrugated silver cathode to increase efficiency [18]. In another paper on plasmonic devices Ji and associates demonstrate the long range surface plasmon (LRSP) mode and cladding mode in a gold stripe through both theoretical and experimental approaches [19].

Chen et. al. report a photonic crystal constituting extraordinarily thick well-aligned planar cholesteric liquid crystal (CLC) cells using a field-assisted self-assembly technique [20]. This work further explores the role of CLCs in slow light production. Continuing with the theme of photonics, Cheng and colleagues discuss the photonic structure of a micro-ring resonator based on liquid source chemical vapor deposition (LSCVD) deposited high-quality silicon nitride (Si₃N₄) films with a low stress and optical loss. The results show that such films are highly promising platforms for integrated photonic applications [21].

Yi and colleagues present a multimode interference (MMI) waveguide sensor for detecting effective anti-inflammatory concentrations of peimine as fritillaria alkaloid drugs. The waveguide sensor is fabricated from erbium-containing cross-linked copolymer and organic–inorganic grafting PMMA material showed multi-hydrogen-bonding affinity interactions between the tested drug and the sensing polymer [22]. Continuing on the theme of sensing Yu and associates report a compact fiber-optic Fabry-Perot interferometric (FFPI) sensor for volatile organic compounds. The gas insensitive sensor was found to be highly sensitive to VOCs [23]. Magneto-optics is an emerging field of optics that explores the interplay of magnetic fields and materials. Miles et. al. explore the phenomenon of faraday rotation in composites of the ferromagnetic nanoparticle FePt [24]. Mizuguchi et. al. reports the usefulness of laser processing technique in welding weld poly(methyl methacrylate) (PMMA) substrates using a dendrite pattern of a quenched melt [25].

The discovery of graphene and other 2D materials have brought about a revolution in electronic materials, with them being studied for a wide variety of applications. In this issue Liu and associates report moisture responsive actuators based on graphene oxide (GO), they have demonstrated crawlers and claw robots based on moisture responsive graphene oxide films [26]. On a more fundamental note Yue et. al. have studied the evolution of fluorescence in photoreduced GO films. This work discusses the observed fluorescence in terms of the chemical composition of the GO [27].

DNA based photonics has grown leaps and bounds in the last decade, this exotic biomaterial has been tried, tested and has proven its mettle as a viable sustainable resource for photonics. Suzuki and colleagues report on DNA light amplification systems for compact photonic devices. Hemicyanine incorporated DNA-CTMA (cetyltrimethylammonium) showed strong light emission. For film preparation they have described a newly developed immersion method resulting in better film performance in intensity, threshold value and durability [28]. Lee et. al reports on the application of 3D cellular cell chip for evaluation of anticancer drug. The cells proliferating on 3D scaffold was found to be more resistant to anticancer drugs compared to those in 2D cell culture [29]. A study on air-clad broadband waveguide device using micromolded high performance polyimde combind with a robust and silica-based inverted opal substrate is described by Khan and coworkers [30].

We would like to express our sincere thanks to Honorary Chair Prof. Paras N. Prasad and one of International Chairs Prof. Francois Kazjar for their support and help in its organization (Fig. 2). Special thanks are due to the International Advisory Committee, International Program Committee, and also Local Organizing Committee for their great works and commitments for the conference organization, offering not only an outstanding scientific program, but also excellent conference facilities for both presentations and associated discussions. We appreciate to conference secretary, Prof. Tae-Dong Kim and Prof. Prem Prabhakaran for their untiring efforts and assistance for the conference. We also wish to thank various institutions, and corporations which provided support for the conference, namely: (i) Polymer Society of Korea, (ii) Korean Chemical Society, (iii) Korean Society of Photoscience, (iv) Hannam Univ. BK21⁺ Center for BT-IT Hybrid Nanomaterials, (v) Daejeon International Marketing Enterprise, (vi) The Korean Federation of Science and Technology Societies, (vii) Korea Tourism Organization, (viii) Asian Office of Aerospace Research and Development, (ix) Office of Naval Research Global, (x) LG Chem, (xi) BioActs, (xii) TecSco, and (xiii) Tavoro.

 

Fig. 2 Representatives of ICFPAM 2018 organizers. From left; Profs. Ileana Rau, Eunkyoung Kim, Paras N. Prasad, Francois Kajzar, Kwang-Sup Lee, Aurelia Meghea, Ryszard Kozlowski, and Serge Cosnier.

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We hope that this issue would be very useful to the researchers for their continued effort in the advancement of organics and polymers with photonic functions. We are thankful to all of authors and reviewers for their excellent contributions.2017. 06, Kwang-Sup LeeEunkyoung KimHong-Bo SunAlex K-Y. JenGuest Editors