Controlled folding of synthetic polymer chains through the formation of positionable covalent bridges

Covalent bridges play a crucial role in the folding process of sequence-defined biopolymers. This feature, however, has not been recreated in synthetic polymers because, apart from some simple regular arrangements (such as block co-polymers), these macromolecules generally do not exhibit a controlled primary structure-that is, it is difficult to predetermine precisely the sequence of their monomers. Herein, we introduce a versatile strategy for preparing foldable linear polymer chains. Well-defined polymers were synthesized by the atom transfer radical polymerization of styrene. The controlled addition of discrete amounts of protected maleimide at precise times during the synthesis enabled the formation of polystyrene chains that contained positionable reactive alkyne functions. Intramolecular reactions between these functions subsequently led to the formation of different types of covalently folded polymer chains. For example, tadpole (P-shaped), pseudocyclic (Q-shaped), bicyclic (8-shaped) and knotted (alpha-shaped) macromolecular origamis were prepared in a relatively straightforward manner

Internal Morphology Controllable Self Assembly in Poly lonic Liquid Nanoparticles

Precise control of the interior and outer shapes of polymer nanoparticles has found broad interest in nanosciences, for example, in fundamental studies of their physical properties, colloidal behavior, and corresponding applications. Realizing such control below the 50 nm scale i.e., a size scale close to individual polymer chains requires accurate manipulation of polymerization techniques and a judicious choice of the chemical structure in monomers and or polymers. Here, we constructed a series of well defined sub 50 nm homopolymer nanoparticles with controllable shape and highly ordered, complex internal structures with sub 5 nm domain spacings, starting from 1 vinyl 1,2,4 triazolium type ionic liquids in a one pot dispersion polymerization. With cryogenic electron microscopy and tomography, a morphological evolution of particle shape and interior at this extremely small size end, unusual for polymer colloids, was identified and investigated in detai

Influence of Thiazole Modified Carbon Nitride Nanosheets with Feasible Electronic Properties on Inverted Perovskite Solar Cells

Effective, solution processable designs of interfacial electron transporting layers ETLs or hole blocking layers are promising tools in modern electronic devices, e.g., to improve the performance, cost, and stability of perovskitebased solar cells. Herein, we introduce a facile synthetic route of thiazole modified carbon nitride with 1.5 nm thick nanosheets which can be processed to a homogeneous, metal free ETL for inverted perovskite solar cells. We show that thiazole modified carbon nitride enables electronic interface enhancement via suppression of charge recombination, achieving 1.09 V in Voc and a rise to 20.17 mA cm2 in Jsc. Hence, this report presents the successful implementation of a carbon nitride based structure to boost charge extraction from the perovskite absorber toward the electron transport layer in p i n devices