Polymer synthesis and reactions

Thermally stable and photosensitive polymers have been widely developed in recent years for their applications in the electronic packaging such as buffer coating, passivation layers, and insulation layers for redistribution in microelectronics due to their excellent thermal and reasonable dielectric properties. This review describes the recent progress of TSPSPs in the last decade and focuses on their design concept. After a brief introduction of the basic patterning procedure, various chemistries on the design of TSPSPs are highlighted along with two major patterning methodologies such as positive- and negative-working polymers. Furthermore, new applications of TSPSPs, such as low dielectric materials, high refractive index lenses, resists for ITO patterning, and π-conjugated polymers for organic-field effect transistors, are also introduced.

The development of reversible-deactivation radical polymerization (RDRP) has made a great contribution not only to control of molecular weight and terminal structures but also to precise syntheses of copolymers. In particular, introducing a new concept into RDRP allows ‘sequence control’, which might lead to construction of ‘alphabet polymer’ bearing well-defined sequence like peptides in nature. Herein, some methodologies to realize sequence control based on RDRP are reviewed.

In this review, we summarize the use of Diels–Alder reaction in the synthesis of arylene-based polymers, including polyphenylenes and ladder polymers, as well as graphene nanoribbons. These polymer materials are structurally related to each other, but rarely discussed all together in a same context. The importance and versatility of the Diels–Alder polymerization is highlighted for the synthesis of such polymers with various potential applications, for example, as polymer electrolyte membrane and organic semiconductors.

Our recent studies on the development of conjugated polymer synthesis via direct arylation polycondensdation (DArP) are summarized. Based on an appropriate molecular design and adjustment of the catalytic system for DArP, a variety of conjugated polymers, such as low-band-gap polymers with the strong acceptor moieties and regioregular poly(3-hexylselenophene) are successfully synthesized. These results demonstrate potential and utility of DArP as an alternative conjugated polymer synthesis methodology.

Synthesis and thermal properties of poly(oligomethylene-cyclopentylene)s and poly(oligomethylene-cyclohexylene)s with regulated regio- and stereochemistry are described. Pd complexes with diimine ligands promote controlled isomerization polymerization of 4-alkylcyclopentenes and alkenylcyclohexanes to afford poly(oligomethylene-1,3-cyclopentylene)s with trans structure and poly(oligomethylene-1,4-cyclohexylene)s with trans or cis structure, respectively. Poly(ethylene-1,2-cyclopentylene) with cis and trans-stereochemistry can be obtained by Fe- and Co-catalyzed cyclopolymerization of 1,6-heptadiene, respectively. The thermal properties of the poly(oligomethylene-cyclopentylene)s and poly(oligomethylene-cyclohexylene)s are compared to those of previously reported polymers with different regio- or stereochemistry.

In this focus review, our recent progress on hybrid polymers and supramolecules utilizing silicon and arsenic is overviewed. Novel materials design based on polyhedral oligomeric silsesquioxane (POSS) has been realized by focusing on the symmetry. Practical synthetic methods have opened new avenue to experimental studies on organoarsenic compounds.

Direct arylation polycondensation has been investigated to develop efficient synthetic methods of conjugated polymers for use in optoelectronic applications. The optimization of reaction conditions achieved high molecular weights and minimal structural defects in the recurring structures. The optimized direct arylation method has several advantages over conventional methods, e.g., fewer synthetic steps, and high-molecular-weight and high-purity polymer. The high-quality polymeric materials exhibited superior performance to those obtained using a conventional method when used in organic photovoltaics and field-effect transistors.