Fundamentals of Conjugated Polymer Blends, Copolymers and Composites

Preface

The conjugated polymers (CPs) are considered as path-breaking discovery, a Serendipity indeed!!!, that has not only revolutionized the area of material science but also changed the face of nanotechnology. It is apt to highlight and worth mentioning here that though their discovery has been rewarded with Year 2000's Chemistry Nobel Prize to the discoverers Prof. Heeger, Prof. Shirakawa, and Late Prof. MacDiarmid, their wealth of prevalent applications that were actually based on strategic combination of CPs with a variety of organic/inorganic materials (bulk- or nano-size) in the form of blends (BLNs), conjugated copolymers (CCPs), composites (CMPs) [bulk or nanocomposites (NCs)], or hybrids (HYBs) have played a pivotal role in demonstrating and advancing their techno-commercial utility. Interestingly, the above area is the best example of power of interdisciplinary research, cross-country collaborations, and industrial partnership, for successful implementation of knowledge and ideas into life-changing products. Therefore, I strongly feel that an interdisciplinary research-oriented dedicated book covering the elementary concepts and recent advancements in the area is necessary to expose current challenges, highlight future perspectives, and stimulate thought process for evolution of novel materials and technologies. This edited book is the first of its own kind that provides a single-source solution to specifically address the fundamentals and applications of CP-based mixed systems, i.e., BLNs, CCPs, and CMPs with special focus on interdisciplinary and application-oriented research and comprehensive literature account. Accordingly, the book is organized into 14 chapters that are subdivided into four sections viz. Multiphase Systems: Synthesis, Properties, and Applications (Chapters 1-4); Energy Harvesting and Storage Materials (Chapters 5-8); Advanced Materials for Environmental Applications (Chapters 9-11); and Sensing and Responsive Materials (Chapters 12-14).

The first section highlights the fundamental aspects of mixed system constituted by strategic combination of doped and undoped CPs with a variety of organic/inorganic materials (bulk- or nano-size) to form BLNs, CCPs, and CMPs/NCs/HYBs. These advanced materials have been demonstrated for techno-commercial utility in diverse areas including electronics and optoelectronics; energy harvesting and storage, environmental pollution, and corrosion control; biology and biomedicals; sensing and responsive materials, etc. Chapter 1 deals with their definitions, types, importance, synthetic routes, and practical applications including the state of the art in the area. The special emphasis has been given to the combination of CPs with a variety of materials like carbonaceous fillers [e.g., fullerene derivatives like PCBM, carbon nanotubes (CNTs), nanofibers (CNFs), graphene analogs, carbon dots (C-Dots), graphene quantum dots (GQDs)]; inorganic nanofillers (e.g., silica or various clays); metal/inorganic nanoparticles (NPs) (e.g., Au/Ag NPs, dielectric/magnetic/redox-active particles like ZnO, V2O5, MnO2, Co3O4, Cu2O, Y2O3, Nb2O5, RuO2, WO3, TiO2, BaTiO3, ?-Fe2O3, BaTiO3, Fe3O4, etc.); semiconductors [quantum confined nanomaterials (QCNs) and nanocrystals (NCRs) like quantum dots (QDs), nanorods (NRs), nanowires (NWs), nanotubes (NTs), tripods, tetrapods, multipods, etc.] to form advanced BLNs, CCPs, and CMPs/NCs/HYBs. Chapter 2 provides a comprehensive account of the transition metal oxides-filled polyaniline (PANI) matrix-based NCs, including their synthesis, properties, and applications. Chapter 3 focuses on the organic/inorganic NCs/HYBs based on strategic combination of various CPs with QCNs (like inorganic semiconducting NPs/NCRs and carbonaceous analogues, e.g., GQDs or C-Dots). The specific advantages of such systems, various synthesis strategies, and their optoelectronic properties have also been discussed. The applicability of these NCs has been demonstrated and discussed for optoelectronic applications [like solar cells (both photovoltaic and dye-sensitized solar cells) and light-emitting diodes (LEDs)], via suitable examples from open literature. Finally, Chapter 4 highlights the graphene-based CP NCs and gives brief account of their optoelectronic and biological applications.

The second section discusses the energy harvesting and storage possibilities with above systems with special reference to organic photovoltaics (OPVs), thermoelectrics (TEs), Li-ion batteries (LIBs), and supercapacitors (SCs). In particular, Chapter 5 highlights the promise of CPs-based BLNs, CCPs, and CMPs/NCs/HYBs as an active material for solar cells and reviews the performance of related OPV devices. The inherent advantages of these systems (in terms of panchromatic solar absorption, phase segregation driven bulk-heterojunction morphology, efficient charge separation and improved transport, leading to efficient PV action) and various material combinations have also been discussed with suitable examples. Chapter 6 outlines the specific advantages of doped CPs (ICPs)-based TE materials (e.g., low density, solution processability, low thermal conductivity, tunable conductivity, and Seeback coefficient) over conventional inorganic TE materials. Particularly, the ICP/inorganic NCs (containing inorganic NPs, CNTs, graphene, metals, and their compounds), their TE properties, and actual TE performances have been comprehensively discussed via suitable examples. Chapter 7 sheds light on ICP/inorganic NCs [based on combination of ICPs like PANI, polypyrrole (PPy), or polythiophene (PTh) with inorganics like LiFePO4, MnO2, V2O5, Si, SnO2, Fe2O3, etc.] as high-performance cathodic and anodic materials for LIBs. It has been systematically highlighted that ICPs-based matrices act as soft cushion for inorganic fillers to accommodate for drastic volume changes and to mitigate mechanical stress, thereby preventing the electrode failure and improving cyclability. In addition, they improve the conductivity of the system and facilitate Li+ insertion/extraction rates, resulting in enhancement of rate capacity of LIBs. Finally, Chapter 8 talks about SCs, which are most promising energy storage alternative for portable electronics and HYB electric vehicles (HEVs). In particular, the PPy/inorganic NCs for electrochemical SCs are reviewed, with emphasis on required structural, chemical, and physical requirements, potential materials, important device parameters and SC performance, well supported by related literature examples.

The third section outlines the environmental applications of above systems including their utility in electromagnetic interference (EMI) shielding, water purification, and corrosion protection of metals. In particular, Chapter 9 covers overview of fundamentals of EMI shielding, theoretical aspects of shielding, and experimental techniques for measurement of shielding effectiveness, followed by detailed discussion on potential EMI shielding materials with main emphasis on ICP-based BLNs and CMPs. Chapter 10 explains corrosion phenomenon, possible solutions, and characterization techniques, in context of ICPs/CP-based NCs, which limit the corrosion by providing the anodic protection, ennobling the surface, and by exerting barrier effect toward a variety of corrodants. The superior anticorrosion performances of organic/inorganic filler-loaded NCs have been highlighted via appropriate examples and data. Chapter 11 emphasizes the pollutant adsorption capabilities of ICPs/CPs-based CMPs/NCs/HYBs and demonstrates their potential for wastewater treatment. Proper attention has been given to adsorption phenomenon, governing equations, and important parameters, with parallel comparison of purification capabilities of PANI-, PPy-, and PTh-based systems.

The fourth and final section is based on the redox property, electroactivity, and polarizability of CPs/ICPs-based systems. More specifically, it deals with the advanced sensing and responsive materials covering applications in the areas of chemical sensors, biosensors, and electrorheological (ER) fluids. Chapter 12 provides current trends in chemical sensor research particularly, where CPs/ICPs-based NCs are exploited as detecting elements. In particular, the device architecture, active layer forming methods, sensing mechanism, important performance indices (sensitivity, selectivity, response/recovery time, performance stability), sensing performance in the presence of various analytes, and specific advantages have been highlighted and thoroughly discussed via suitable examples. Chapter 13 overviews recent works dealing with synthesis and characterization of CP/CP NCs and highlights their applications related to biosensors including catalytic biosensors and bio-affinity biosensors. The last contribution, i.e., Chapter 14, focuses on the recent R&D and state of the art of the PANI NCs-based suspensions and ER fluids based on the same. Especially, the advantages of using anisotropic nanostructured PANI as ER dispersal phase have been highlighted, and performance of related NCs has been compared.

The above chapters cover all perspectives of these multiphase systems, including their relevance, synthetic routes, and practical applications that have been complemented by comprehensive literature account covering past and present research, key developments, and state of the art in the area. Extra care has been taken to simplify the matter and to facilitate the understanding via the specifically designed and selected graphics, i.e., illustrations, schematics, and figures; tabulated information, case studies, and many more literature examples. Due attention has also been given at the end of specific chapters to address the current challenges and future aspects and to stimulate the grey matter and ignite though process. I feel that a...