Toward Fully Controllable Monomers Sequence: Binary Organocatalyzed Polymerization from Epoxide/Aziridine/Cyclic Anhydride Monomer Mixture.

The sequence of monomers within a polymer chain plays a pivotal role in determining the physicochemical properties of the polymer. In the copolymerization of two or more monomers, the arrangement of monomers within the resulting polymer is primarily dictated by the intrinsic reactivity of the monomers. Precisely controlling the monomer sequence in copolymerization, particularly through the manipulation of catalysts, is a subject of intense interest and poses significant challenges. In this study, we report the catalyst-controlled copolymerization of epoxides, N-tosyl aziridine (TAz), and cyclic anhydrides. To achieve this, a binary catalyst system comprising a Lewis acid, triethylborane, and Brønsted base, t-BuP1, was utilized. This system was utilized to regulate the selectivity between two catalytic reactions: ring-opening alternating copolymerization (ROAC) of epoxides/cyclic anhydrides and ROAC of TAz/cyclic anhydrides. Changing the catalyst ratio made it possible to continuously modulate the resulting poly(ester-amide ester) from ABA-type real block copolymers to gradient, random-like, reversed gradient, and reversed BAB-type block-like copolymers. A range of epoxides and anhydrides was investigated, demonstrating the versatility of this polymerization system. Additionally, density functional theory calculations were conducted to enhance our mechanistic understanding of the process. This synthetic method not only provides a versatile means for producing copolymers with comparable chemical compositions but also facilitates the exploration of the intricate relationship between monomer sequences and the resultant polymer properties, offering valuable insights for advancements in polymer science.

Facile Blending Strategy for Boosting the Conjugated Polymer Semiconductor Transistor's Mobility.

The optimization of field-effect mobility in polymer field-effect transistors (FETs) is a critical parameter for advancing organic electronics. Today, many challenges still persist in understanding the roles of the design and processing of semiconducting polymers toward electronic performance. To address this, a facile approach to solution processing using blends of PDPP-TVT and PTPA-3CN is developed, resulting in a 3.5-fold increase in hole mobility and retained stability in electrical performance over 3 cm2 V-1 s-1 after 20 weeks. The amorphous D-A conjugated structure and strong intramolecular polarity of PTPA-3CN are identified as major contributors to the observed improvements in mobility. Additionally, the composite analysis by X-ray photoelectron spectroscopy (XPS) and the flash differential scanning calorimetry (DSC) technique showed a uniform distribution and was well mixed in binary polymer systems. This mobility enhancement technique has also been successfully applied to other polymer semiconductor systems, offering a new design strategy for blending-type organic transistor systems. This blending methodology holds great promise for the practical applications of OFETs.

Donor-Acceptor Effect of Carbazole-Based Conjugated Polymer Electrets on Photoresponsive Flash Organic Field-Effect Transistor Memories.

The molecular structure of polymer electrets is crucial for creating diverse functionalities of organic field-effect transistor (OFET) devices. Herein, a conceptual framework has been applied in this study to design the highly photoresponsive carbazole-based copolymer electret materials for the application of photoresponsive OFET memory. As an electret layer, two 1,8-carbazole-based copolymers were utilized; the copoly(CT) consisted of carbazole as the donor group and thiophene as the π-spacer, whereas the copoly(CBT) was further introduced as an acceptor moiety, benzothiadiazole, for comparison. Both copolymers exhibited efficient visible-light absorption and photoluminescence quenching in the film state, indicating the formation of a considerable number of nonemissive excitons, one of the crucial factors for achieving photoinduced recovery behavior in OFET memories. Compared to copoly(CT) with the pure donor system, faster and more effective photoinduced recovery behavior was discovered in the copoly(CBT) with the conjugated donor-acceptor structure because of the coexistence of the conjugated donor and acceptor groups. Thus, the dissociation of the generated excitons facilitated the stimulating of the unique ambipolar trapping property, resulting in the high-density data storage devices with multilevel current states. In addition, the nonvolatile and durable characteristics demonstrated the feasibility in application of memory and photorecorders.