Synthesis of conjugated polymers through light- induced step-growth polymerization

Abstract

Conjugated conducting polymers have attracted a great deal of attention since their discovery 50 years ago because of their distinctive conductive properties and potential uses in fuel cells, actuators, adhesives, and electronic components like organic field- effect inverters, photovoltaic panels, and light-emitting devices. In recent years, these materials have been very important in making people's living spaces more comfortable. As a result, it is critical to create unique, high-performance conjugated conductive materials. Electropolymerization, oxidative polymerization, and coupling processes are some of the most statistically significant xxiolüene synthesis of these polymers (e.g., Suzuki and Yamamoto). Polymers with distinct morphologies and, therefore, diverse physical and chemical characteristics can be produced based on the synthetic process employed. Additionally, they can be blended with other synthetic polymers to enhance their processability and characteristics. Photopolymerization is a fast-growing method due to its many benefits. For example, it is solvent-free, energy-efficient, and appropriate for heat-sensitive materials. In addition, photopolymerization only proceeds in the lighted region, resulting in both temporal and spatial resolutions that are complete. These advantages make it possible to produce films and intricate three-dimensional objects for industries including protective coating, adhesive, automotive, microcircuit, and semiconductor. High spatial resolution and a wide variety of potential uses are provided by the use of photosensitive resins in cost and easy additive manufacturing methods. By exposing photosensitive compounds, particularly photoinitiators, to ultraviolet or visible light, a chain reaction is initiated that transforms a monomer into a polymer.. Unlike traditional chain polymerizations, photoinduced step-growth polymerizations do not need the use of an initiator. When two monomers with different functions react at equal molar concentrations, a difunctional polymer is formed. During the first stages of polymerization, just a single reaction mechanism is at work, and the total increase in molecular weight is slow. In contrast to a chain-growth process, the phases of initiation, propagation, and termination are thus omitted. In the first part of the thesis, we provide a novel, easy photochemical method for step- growth polymerization xxiolüene synthesis of polypyrene (PPy). PPy synthesis using the photo-induced polymerization technique in the presence of iodonium salt (DPI) was carried out with low cost and high efficiency. A thorough examination of the structural, morphological, electrochemical, and molecular weight features of the polymers indicated that the DPI/Py ratio has a significant impact on the chain length and on the efficiency of electropolymerization. This technique is very applicable to functional pyrenes and other conjugated monomers. In the second part of the thesis, we describe the manufacture of microspherical conjugated polymer structures based on carbazole, an essential material for OLED, OPV, and electronic circular dichroism applications. A novel photochemical method xxiiolüene metal-free synthesis of a hollow spherical conjugated polymer is presented. CBP, which contains both carbazole and biphenyl units, was polymerized at 350 nm in the presence of iodonium salt (Ph2I+PF6-), and the resulting polymers were studied. The dedoping method resulted in the transformation of self-assembled microspheres with a great distance into more homogeneous spherical structures, according to atomic force microscopy (AFM) and transmittance electron microscopy (TEM) analyses. In the last part of the thesis, xxiiolüene synthesis of 9-(4-vinylphenyl) carbazole-based polymers, we disclosed a completely photochemical synthetic strategy that involves the sequential and simultaneous combination of free radical and step-growth polymerization processes. As a result of diminishing crystallinity in the sequential technique, the resultant polymers have a smooth surface. The following photoinitiated step-growth polymerization of the carbazole groups using diphenyliodonium hexafluorophosphate (DPI) resulted in highly branching and cross-linked polymers with microspheres on the surface, as seen by TEM examination. Simultaneous photoinitiated free radical and step-growth polymerizations utilizing DPI produced cross-linked polymers with scattered distribution in the one-pot method.