The field of supramolecular polymers is rapidly expanding; however, the exploitation of these systems as functional materials is still elusive. To become competitive, supramolecular polymers must display microstructural order and the emergence of new properties upon copolymerization. To tackle this, a greater understanding of the relationship between monomers’ design and polymer microstructure is required as well as a set of functional monomers that efficiently interact with one another to synergistically generate new properties upon copolymerization. Here, we present the first implementation of frustrated Lewis pairs into supramolecular copolymers. Two supramolecular copolymers based on π-conjugated O -bridged triphenylborane and two different triphenylamines display the formation of B–N pairs within the supramolecular chain. The remarkably long lifetime and the circularly polarized nature of the resulting photoluminescence emission highlight the possibility to obtain an intermolecular B–N charge transfer. These results are proposed to be the consequences of the enchainment of B–N frustrated Lewis pairs within 1D supramolecular aggregates. Although it is challenging to obtain a precise molecular picture of the copolymer microstructure, the formation of random blocklike copolymers could be deduced from a combination of optical spectroscopic techniques and theoretical simulation.

Precise oligomeric materials constitute a growing area of research with implications for various applications as well as fundamental studies. Notably, this field of science which can be termed macro‐organic chemistry, draws inspiration from both traditional polymer chemistry and organic synthesis, combining the molecular precision of organic chemistry with the materials properties of macromolecules. Discrete oligomers enable access to unprecedented materials properties, for example, in self‐assembled structures, crystallization, or optical properties. The degree of control over oligomer structures resembles many biological systems and enables the design of materials with tailored properties and the development of fundamental structure–property relationships. This Review highlights recent developments in macro‐organic chemistry from synthetic concepts to materials properties, with a focus on self‐assembly and molecular recognition. Finally, an outlook for future research directions is provided.

Crystallinity is seldomly utilized as part of the microphase segregation process in ultralow-molecular-weight block copolymers. Here, we show the preparation of two types of discrete, semicrystalline block co-oligomers, comprising an amorphous oligodimethylsiloxane block and a crystalline oligo-l-lactic acid or oligomethylene block. The self-assembly of these discrete materials results in lamellar structures with unforeseen uniformity in the domain spacing. A systematic introduction of dispersity reveals the extreme sensitivity of the microphase segregation process toward chain length dispersity in the crystalline block.

Discrete length block co-oligomers (BCOs) comprised of a crystalline and an amorphous block are a new class of materials that gives highly ordered lamellar morphologies at small length scales. Here, we show the preparation of discrete, isotactic oligo l- and d-lactic acid (olLA and odLA) homoblocks followed by ligation to oligodimethylsiloxane (oDMS), affording a library of crystalline–amorphous BCOs that vary in molecular weight and composition. Mixing the two enantiomeric BCOs or homoblocks results in the formation of the corresponding stereocomplex. The properties and phase behavior of the isotactic (block co)oligomers and the stereocomplexes thereof are studied using differential scanning calorimetry and small-angle X-ray scattering. A systematic study of the isotactic homoblock lengths and crystal structure confirmed the formation of a 103 helix with a monomeric rise of 0.3 nm, whereas the stereocomplex adopts a 31 helix. The same type of crystal structure was found for the isotactic and stereocomplex of BCOs giving rise to the formation of lamellar morphologies at room temperature as a result of crystallization of the oLA blocks. Distorted lamellar structures were found in BCOs that preorganize into nonlamellar morphologies prior to crystallization. The stereocomplex BCOs shows more crystal defects and a loss of long-range ordering in the microstructure due to the larger driving force for crystallization. Hence, the balance between chain length, block volume, and the crystallization strength are of major importance for the formation of the final structure with the least defects.

Nanomaterials with highly ordered, one- or two-dimensional molecular morphologies have promising properties for adaptive materials. Here, we present the synthesis and structural characterization of dinitrohydrazone (hydz) functionalized oligodimethylsiloxanes (oDMSs) of discrete length, which form both 1- and 2D nanostructures by precisely controlling composition and temperature. The morphologies are highly ordered due to the discrete nature of the siloxane oligomers. Columnar, 1D structures are formed from the melt within a few seconds as a result of phase segregation in combination with π–π stacking of the hydrazones. By tuning the length of the siloxane, the synergy between these interactions is observed which results in a highly temperature sensitive material. Macroscopically, this gives a material that switches reversibly and fast between an ordered, solid and a disordered, liquid state at almost equal temperatures. Ordered, 2D lamellar structures are formed under thermodynamic control by cold crystallization of the hydrazones in the amorphous siloxane bulk via a slow process. We elucidate the 1- and 2D morphologies from the nanometer to molecular level by the combined use of solid state NMR and X-ray scattering. The exact packing of the hydrazone rods within the cylinders and lamellae surrounded the liquid-like siloxane matrix is clarified. These results demonstrate that controlling the assembly pathway in the bulk and with that, tuning the nanostructure dimensions and domain spacings, material properties are altered for applications in nanotechnology or thermoresponsive materials.