A Block Supramolecular Polymer and Its Kinetically Enhanced Stability

Competition and cooperation between steric hindrance and hydrogen bonding of supramolecular discs

We previously reported supramolecular polymers formed by π-π stacking between disc-shaped hexamers (rosettes) of barbituric acid-functionalized π-conjugated molecules. Herein, we investigated the impact of amide-mediated hydrogen bonding along two types of polymer backbones formed by distinct stacking of rosettes. The stabilization of the hydrogen bonds strongly depends on the intrinsic stacking arrangement of rosettes, which competes with the amide hydrogen-bonding.

Elucidating the Boundary of Intercalation vs Sequestration in Supramolecular Polymers by Retrosynthetic Design Toward the Construction of Complex Supramolecular Systems

Controlled social self-sorting by intercalation can offer distinct properties at the supramolecular level that go beyond the sum of its parts. Likewise, controlling narcissistic self-sorting by sequestration can induce unique system properties. In contrast, the interface between the two cases has hitherto remained underexplored, and clear design rules remain elusive. Herein it is demonstrated that by fine-tuning the molecular similarity of supramolecular synthons, intricate control over concerted supramolecular equilibria can be achieved. By reducing the molecular similarity, a former intercalator can be tuned to become a strong or weak sequestrator. Understanding these roles in binary mixtures allows to rationalize more complex tertiary systems. Consequently, the influence of an uncommon dual sequestration mechanism is revealed. Further, an unprecedented hybrid mechanism between supramolecular intercalation and sequestration can be demonstrated. We are hopeful that the results presented herein will contribute to the development and understanding of concerted processes in complex supramolecular systems.

Redox-Controlled, Sequential Self-Sorting of Supramolecular Assemblies in Model Protocells

Self-sorting of cellular components is essential for maintaining order and function in living systems, enabling complex processes to operate seamlessly. Emulating such self-sorting in synthetic self-assembly, however, has conventionally relied on structural or chirality mismatches of monomers yielding self-sorted systems under thermodynamic conditions. In contrast, reaction-coupled, kinetically controlled self-assembly, ubiquitous in biological systems, is critical for achieving spatiotemporal characteristics. Extending this principle to temporally self-sorted synthetic assemblies is key to developing multi-component biomimetic systems. Herein, we present a strategy towards this direction, to achieve sequential self-sorting of supramolecular assemblies through differences in the chemical-reactivity of monomers, coupled to redox-reactions. This approach exploits the distinct redox potentials of monomers to achieve precise temporal-control over self-sorting, while inherent structural mismatches among monomers ensure the kinetic stability of self-sorted state. Reduction reactions transiently disrupt their assemblies into dormant inactive monomeric states, while subsequent kinetically controlled reassembly occurs via reversible oxidation reactions. Finally, utilizing this sequential self-sorting, we aim to mimic multicomponent cellular self-organization by demonstrating the kinetically controlled growth of self-sorted structures in the presence of model protocells, using lipid vesicles as compartments. Although spatial-distribution remains non-selective, the dormant monomeric states facilitate monomer encapsulation and the unprecedented stepwise-formation of self-sorted assemblies within model protocells.

Enhanced Stability and Properties of Benzene-1,3,5-Tricarboxamide Supramolecular Copolymers through Engineered Coupled Equilibria

Improving the stability of multi-component and functional assemblies such as supramolecular copolymers without impeding their dynamicity is key for their implementation as innovative materials. Up to now, this has been achieved by a trial-and-error approach, requiring the time-consuming characterization of a series of supramolecular coassemblies. We report herein that this is possible to significantly enhance the stability of supramolecular copolymers by a minimal change in the chemical nature of one of the interacting monomers. This is achieved by replacing an ester function by an ether function in the structure of a chiral benzene-1,3,5-tricarboxamide (BTA) monomer, used as "sergeant", coassembled with achiral monomers, the "soldiers". Pseudo-phase diagrams, constructed by probing the nature of the coassemblies with multifarious analytical techniques, confirm that the greater stability of the resulting copolymers is mainly due to the minimization of competing species. This leads to better rheological and catalytic properties of the corresponding supramolecular copolymers. Favouring coassembly over undesired assembly pathways must be considered as a blueprint for the development of better-performing supramolecular multi-component systems.

Tailored Nucleation-Growth Strategy for Precise Self-Assembly of Block Copolymers

The self-assembly of block copolymers (BCPs) to form nanostructures of various morphologies and controllable dimensions has been a very promising research area in nanotechnology in recent decades. This concept mainly summarizes the recent advances in precise and controllable self-assembly of BCPs through a tailored nucleation-growth strategy to modulate the self-assembly behavior of the BCPs. These efforts have led to a better understanding of the self-assembly mechanisms and opened new possibilities for creating novel materials with designable properties. We hope that the concept is more than a periodical summary of previous research work and can provide valuable inspiration for the research field.

Amplification and Attenuation of Asymmetry via Kinetically Controlled Seed-Induced Supramolecular Polymerization

The amplification of asymmetry in supramolecular polymers has recently garnered significant attention. While asymmetry amplification has predominantly been explored under thermodynamic conditions, the kinetic aspect of this process unveils intriguing observations, yet is scarcely reported in the literature. Herein, drawing inspiration from macromolecular systems, we propose a novel strategy for enhancing asymmetry in supramolecular polymers through a seed-induced supramolecular polymerization approach under kinetic conditions, employing a naphthalene diimide-derived monomer (ANSG) for template-induced supramolecular polymerization, utilizing adenosine triphosphate (ATP) and pyrophosphate (PPi) as templates. A chiral seed comprising [ANSG-ATP]S effectively amplifies the overall supramolecular asymmetry when exposed to a mixture of achiral templates (PPi) and monomers (ANSG), owing to its efficient seeding characteristics under kinetic conditions. As a result of efficient co-operativity, conversely, employing an achiral seed [ANSG-PPi]S in a mixture of chiral templates (ATP) and monomers (ANSG) results in the attenuation of asymmetry, highlighting the effective modulation achievable through the seeding approach, an unprecedented observation in the field. Exploiting the efficient aggregation-induced emission enhancement (AIEE) of the resultant supramolecular polymers further extends the amplification and attenuation of circularly polarized luminescence (CPL) as a potential function.

A Versatile Strategy toward Donor-Acceptor Nanofibers with Tunable Length/Composition and Enhanced Photocatalytic Activity

Living crystallization-driven self-assembly (CDSA) has emerged as an efficient strategy to generate nanofibers of π-conjugated polymers (CPNFs) in a controlled fashion. However, reports of donor-acceptor (D-A) heterojunction CPNFs are extremely rare. The preparation of these materials remains a challenge due to the lack of rational design guidelines for the D-A π-conjugated units. Herein, we report a versatile CDSA strategy based upon carefully designed D-A-co-oligomers in which electron-deficient benzothiadiazole (BT) or dibenzo[b,d]thiophene 5,5-dioxide (FSO) units are attached to the two ends of an oligo(p-phenylene ethynylene) heptamer [BT-OPE7-BT, FSO-OPE7-FSO]. This arrangement with the electron-deficient groups at the two ends of the oligomer enhances the stacking interaction of the A-D-A π-conjugated structure. In contrast, D-A-D structures with a single BT in the middle of a string of OPE units disrupt the packing. We employed oligomers with a terminal alkyne to synthesize diblock copolymers BT-OPE7-BT-b-P2VP and BT-OPE7-BT-b-PNIPAM (P2VP = poly(2-vinylpyridine), PNIPAM = poly(N-isopropylacrylamide)) and FSO-OPE7-FSO-b-P2VP and FSO-OPE7-FSO-b-PNIPAM. CDSA experiments with these copolymers in ethanol were able to generate CPNFs of controlled length by both self-seeding and seeded growth as well as block comicelles with precisely tunable length and composition. Furthermore, the D-A CPNFs with a BT-OPE7-BT-based core demonstrate photocatalytic activity for the photooxidation of sulfide to sulfoxide and benzylamine to N-benzylidenebenzylamine. Given the scope of the oligomer compositions examined and the range of structures formed, we believe that the living CDSA strategy with D-A-based co-oligomers opens future opportunities for the creation of D-A CPNFs with programmable architectures as well as diverse functionalities and applications.

Catalytic effect of microflow space for supramolecular block co-polymerization of water-soluble porphyrins

Using microflow space, a catalytic effect was achieved for supramolecular polymerization. With increasing reactivity at the polymer end, the selective connection of active monomers formed new block domains, avoiding fast homo-assembly. Binding of less-reactive monomers at the polymer end overcame steric bulkiness, affording a stable supramolecular diblock copolymer (SdiBCP).

Metallosupramolecular Multiblock Copolymers of Lanthanide Complexes by Seeded Living Polymerization

Supramolecular block copolymers, derived via seeded living polymerization, are increasingly recognized for their rich structural and functional diversity, marking them as cutting-edge materials. The use of metal complexes in supramolecular block copolymerization not only offers a broad range of block copolymers through the structural similarity in the coordination geometry of the central metal ion but also controls spectroscopic properties, such as emission wavelength, emission strength, and fluorescence lifetime. However, the exploration of metallosupramolecular multiblock copolymerization based on metal complexes remains quite limited. In this work, we present a pioneering synthesis of metallosupramolecular multiblock copolymers utilizing Eu3+ and Tb3+ complexes as building blocks. This is achieved through the strategic manipulation of nonequilibrium self-assemblies via a living supramolecular polymerization approach. Our comprehensive exploration of both thermodynamically and kinetically regulated metallosupramolecular polymerizations, centered around Eu3+ and Tb3+ complexes with bisterpyridine-modified ligands containing R-alanine units and a long alkyl group, has highlighted intriguing behaviors. The monomeric [R-L1Eu(NO3)3] complex generates a spherical structure as the kinetic product. In contrast, the monomeric [R-L1Eu2(NO3)6] complex generates fiber aggregates as a thermodynamic product through intermolecular interactions such as π-π stacking, hydrophobic interaction, and H-bonds. Utilizing the Eu3+ complex, we successfully conducted seed-induced living polymerization of the monomeric building unit under kinetically regulated conditions. This yielded a metallosupramolecular polymer of precisely controlled length with minimal polydispersity. Moreover, by copolymerizing the kinetically confined Tb3+ complex state ("A" species) with a seed derived from the Eu3+ complex ("B" species), we were able to fabricate metallosupramolecular tri- and pentablock copolymers with A-B-A, and B-A-B-A-B types, respectively, through a seed-end chain-growth mechanism.

Pathway Selection in Temporal Evolution of Supramolecular Polymers of Ionic π-Systems: Amphiphilic Organic Solvent Dictates the Fate of Water

Understanding solvent-solute interactions is essential to designing and synthesising soft materials with tailor-made functions. Although the interaction of the solute with the solvent mixture is more complex than the single solvent medium, solvent mixtures are exciting to unfold several unforeseen phenomena in supramolecular chemistry. Here, we report two unforeseen pathways observed during the hierarchical assembly of cationic perylene diimides (cPDIs) in water and amphiphilic organic solvent (AOS) mixtures. When the aqueous supramolecular polymers (SPs) of cPDIs are injected into AOS, initially kinetically trapped short SPs are formed, which gradually transform into thermodynamically stable high aspect ratio SP networks. Using various experimental and theoretical investigations, we found that this temporal evolution follows two distinct pathways depending on the nature of the water-AOS interactions. If the AOS is isopropanol (IPA), water is released from cPDIs into bulk IPA due to strong hydrogen bonding interactions, which further decreases the monomer concentration of cPDIs (Pathway-1). In the case of dioxane AOS, cPDI monomer concentration further increases as water is retained among cPDIs (Pathway-2) due to relatively weak interactions between dioxane and water. Interestingly, these two pathways are accelerated by external stimuli such as heat and mechanical agitation.

Enzymatic Reaction-Coupled, Cooperative Supramolecular Polymerization

Nature employs sophisticated mechanisms to precisely regulate self-assembly and functions within biological systems, exemplified by the formation of cytoskeletal filaments. Various enzymatic reactions and auxiliary proteins couple with the self-assembly process, meticulously regulating the length and functions of resulting macromolecular structures. In this context, we present a bioinspired, reaction-coupled approach for the controlled supramolecular polymerization in synthetic systems. To achieve this, we employ an enzymatic reaction that interfaces with the adenosine triphosphate (ATP)-templated supramolecular polymerization of naphthalene diimide monomers (NSG). Notably, the enzymatic production of ATP (template) plays a pivotal role in facilitating reaction-controlled, cooperative growth of the NSG monomers. This growth process, in turn, provides positive feedback to the enzymatic production of ATP, creating an ideal reaction-coupled assembly process. The success of this approach is further evident in the living-growth characteristic observed during seeding experiments, marking this method as the pioneering instance where reaction-coupled self-assembly precisely controls the growth kinetics and structural aspects of supramolecular polymers in a predictive manner, akin to biological systems.

Electronically and geometrically complementary perylenediimides for kinetically controlled supramolecular copolymers

The synthesis of 3,4,9,10-benzo[d,e]isoquinolino[1,8-g,h]quinoline-tetracarboxylic diimide (BQQDI) 1 endowed with peripheral trialkoxybenzamide fragments is reported and its self-assembling features investigated. The peripheral benzamide moieties generate metastable monomeric species that afford a kinetically controlled supramolecular polymerization. The electron-withdrawing character of 1 in comparison with previously reported PDIs 2, together with the similar geometry, makes this dye an optimal candidate to perform seeded supramolecular copolymerization yielding four different supramolecular block copolymers. Whilst heteropolymers poly-1-co-2a, poly-2a-co-1 and poly-1-co-2b present an H-type arrangement of the monomeric units, heteropolymer poly-2b-co-1, prepared by seeding the chiral, metastable monomers of 2b with achiral seeds of 1, produces chiral, J-type aggregates. Interestingly, the monosignated CD signal of pristine poly-2b changes to a bisignated CD signal most probably due to the formation of columnar domains around the seeds of 1 which implies the blocky nature of the supramolecular copolymers formed.

Strategies for Synthesizing Supramolecular Block Copolymers

Over the past decade, controlled supramolecular polymerization has been extensively studied and gradually shifted to supramolecular block copolymerization. Supramolecular block copolymers (BCPs) are considered the holy grail for developing supramolecular materials with new functionalities due to their fascinating structures and ability to introduce diverse functions. From a thermodynamic view to kinetic aspects, great progress has been made in the synthetic strategies of BCPs in the past few years. This Concept summarizes various strategies to realize supramolecular block copolymerization. The focus is on providing researchers with a methodological basis for achieving heterogeneous nucleation-elongation.

Noncovalent synthesis of homo and hetero-architectures of supramolecular polymers via secondary nucleation

The synthesis of supramolecular polymers with controlled architecture is a grand challenge in supramolecular chemistry. Although living supramolecular polymerization via primary nucleation has been extensively studied for controlling the supramolecular polymerization of small molecules, the resulting supramolecular polymers have typically exhibited one-dimensional morphology. In this report, we present the synthesis of intriguing supramolecular polymer architectures through a secondary nucleation event, a mechanism well-established in protein aggregation and the crystallization of small molecules. To achieve this, we choose perylene diimide with 2-ethylhexyl chains at the imide position as they are capable of forming dormant monomers in solution. Activating these dormant monomers via mechanical stimuli and hetero-seeding using propoxyethyl perylene diimide seeds, secondary nucleation event takes over, leading to the formation of three-dimensional spherical spherulites and scarf-like supramolecular polymer heterostructures, respectively. Therefore, the results presented in this study propose a simple molecular design for synthesizing well-defined supramolecular polymer architectures via secondary nucleation.

Supramolecular copolymerization of hydrophobic and hydrophilic monomers in liquid crystalline media

In the case of covalent polymers, immiscible polymers can be integrated by covalently linking them together, but such a strategy is not possible in supramolecular polymers. Here we report the supramolecular copolymerization of two porphyrin-based monomers, C10P2H and TEGPCu with side chains bearing cyanobiphenyl (CB) groups at the ends of hydrophobic alkyl or hydrophilic tetraethylene glycol chains, respectively. These monomers undergo self-sorting supramolecular polymerization in highly diluted solutions ([monomer] = 3.4 × 10-9 mol% (2.0 × 10-8 mol L-1)) in nonpolar media due to the incompatibility of the side chains. Surprisingly, these monomers undergo supramolecular copolymerization under high concentration conditions ([monomer] = 7.7 mol%) in the medium of 4-cyano-4'-pentyloxybiphenyl (5OCB) to form a columnar liquid crystalline phase under thermodynamic conditions, where the individual columns are composed of supramolecular block copolymers. The combination of CB ends of both monomers and the 5OCB medium is essential for the two monomers to form an integrated structure in a condensed system without phase separation.

Shape-Assisted Self-Assembly of Hexa-Substituted Carpyridines into 1D Supramolecular Polymers

The extent of the influence that molecular curvature plays on the self-assembly of supramolecular polymers remains an open question in the field. We began addressing this fundamental question with the introduction of "carpyridines", which are saddle-shaped monomers that can associate with one another through π-π interactions and in which the rotational and translational movements are restricted. The topography displayed by the monomers led, previously, to the assembly of highly ordered 2D materials even in the absence of strong directional interactions such as hydrogen bonding. Here, we introduce a simple strategy to gain control over the dimensionality of the formed structures yielding classical unidimensional polymers. These have been characterized using well-established protocols allowing us to determine and confirm the self-assembly mechanism of both fibers and sheets. The calculated interaction energies are significantly higher than expected for flexible self-assembling units lacking classical "strong" non-covalent interactions. The versatility of this supramolecular unit to assemble into either supramolecular fibers or 2D sheets with strong association energies highlights remarkably well the potential and importance of molecular shape for the design of supramolecular materials and the applications thereof.

Cascade Energy Transfer and White-Light Emission in Chirality-Controlled Crystallization-Driven Two-Dimensional Co-assemblies from Donor and Acceptor Dye-Conjugated Polylactides

Achieving predictable and programmable two-dimensional (2D) structures with specific functions from exclusively organic soft materials remains a scientific challenge. This article unravels stereocomplex crystallization-driven self-assembly as a facile method for producing thermally robust discrete 2D-platelets of diamond shape from biodegradable semicrystalline polylactide (PLA) scaffolds. The method involves co-assembling two PLA stereoisomers, namely, PY-PDLA and NMI-PLLA, which form stereocomplex (SC)-crystals in isopropanol. By conjugating a well-known Förster resonance energy transfer (FRET) donor and acceptor dye, namely, pyrene (PY) and naphthalene monoimide (NMI), respectively, to the chain termini of these two interacting stereoisomers, a thermally robust FRET process can be stimulated from the 2D array of the co-assembled dyes on the thermally resilient SC-PLA crystal surfaces. Uniquely, by decorating the surface of the SC-PLA crystals with an externally immobilized guest dye, Rhodamine-B, similar diamond-shaped structures could be produced that exhibit pure white-light emission through a surface-induced two-step cascade energy transfer process. The FRET response in these systems displays remarkable dependence on the intrinsic crystalline packing, which could be modulated by the chirality of the co-assembling PLA chains. This is supported by comparing the properties of similar 2D platelets generated from two homochiral PLLAs (PY-PLLA and NMI-PLLA) labeled with the same FRET pair.

Recognition of atomic-level difference in porphyrin dyads for self-sorted supramolecular polymer growth

Porphyrin dyads (PDMs, where M = Zn and Cu) composed of diphenylporphyrin and tetraphenylporphyrin units, designated as DPDMs and TPDMs, respectively, exhibited remarkable differences in the molecular assemblies depending on the coordination metal ion. Furthermore, TPDMs showed self-sorting behavior during the formation of supramolecular assemblies through the recognition of atomic-level difference.

Two-Dimensional Living Supramolecular Polymerization: Improvement in Edge Roughness of Supramolecular Nanosheets by Using a Dummy Monomer

Supramolecular polymers are formed through nucleation (i. e., initiation) and polymerization processes, and kinetic control over the nucleation process has recently led to the realization of living supramolecular polymerization. Changing the viewpoint, herein we focus on controlling the polymerization process, which we expect to pave the way to further developments in controlled supramolecular polymerization. In our previous study, two-dimensional living supramolecular polymerization was used to produce supramolecular nanosheets with a controlled area; however, these had rough edges. In this study, the growth of the nanosheets was controlled by using a 'dummy' monomer to produce supramolecular nanosheets with smoothed edges.

Supramolecular alternating copolymers with highly efficient fluorescence resonance energy transfer

This article reports alternating supramolecular copolymerization of two naphthalene-diimide (NDI)-derived building blocks (NDI-1 and NDI-2) under thermodynamic control. Both monomers contain a central NDI chromophore, attached to a hydrocarbon-chain and a carboxylic-acid group. The NDI core in NDI-2 is symmetrically substituted with two butane-thiol groups, which makes it distinct from NDI-1. In decane, a 1 : 1 mixture of NDI-1 and NDI-2 shows spontaneous gelation and a typical fibrillar network, unlike the behavior of either of the components individually. The solvent-dependent UV/vis spectrum of the mixed sample in decane shows bathochromically shifted sharp absorption bands and a sharp emission band (holds a mirror-image relationship) with a significantly small Stokes shift compared to those in CHCl3, indicating J-aggregation. In contrast, the aggregated spectra of the individual monomers show broad structureless features, suggesting ill-defined aggregates. Cooling curves derived from the temperature-dependent UV/vis spectroscopy studies revealed early nucleation and a signature of well-defined cooperative polymerization for the mixed sample, unlike either of the individual components. Molecular dynamics simulations predicted the greatest dimer formation tendency for the NDI-1 + NDI-2 (1 : 1), followed by pure NDI-1 and NDI-2. Theoretical studies further revealed a partial positive charge in the NDI ring of NDI-1 when compared to NDI-2, promoting the alternating stacking propensity, which is also favored by the steric factor as NDI-2 is core-substituted with alkyl thiols. Such theoretical predictions fully corroborate with the experimental results showing 1 : 1 stoichiometry (from Job's plot) of the two monomers, indicating alternate stacking sequences in the H-bonded (syn-syn catemer type) supramolecular copolymer. Such alternating supramolecular copolymers showed highly efficient (>93%) fluorescence resonance energy transfer (FRET).

Controlled Noncovalent Synthesis of Secondary Supramolecular Polymers

Dynamic supramolecular polymers, with their functional similarities to classical covalent polymers and their adaptive and self-repairing nature reminiscent of biological assemblies, have emerged as highly promising systems for the design of smart soft materials. Recent advancements in mechanistic investigations and novel synthetic strategies, such as living supramolecular polymerization, have significantly enhanced our ability to control the primary structure of these supramolecular polymers. However, realizing their full functional potential requires expanding their topological diversity in a manner akin to classical polymers as well as achieving precise molecular organization at higher hierarchical levels of self-assembly. In this paper, we present a remarkable advancement in this field, introducing an unprecedented and controlled synthesis of secondary supramolecular polymers. Our innovative strategy combines chirality-controlled surface-catalyzed secondary nucleation and a bioinspired peptide design, effectively stabilizing higher-order assembly. Furthermore, by harnessing this stereoselective nucleation process, we demonstrate the successful synthesis of racemic supramolecular polymers featuring parallelly stacked conglomerate microstructures─a previously unreported topology in synthetic self-assembled systems. Additionally, we elucidate that the extent of secondary supramolecular polymers can be regulated by modulating the enantiomeric excess of the chiral monomers. Consequently, our study unveils new topologies that exhibit enhanced higher-order structural complexity in the realm of supramolecular polymers.

Supramolecular Block Copolymers from Tricarboxamides. Biasing Co-assembly by the Incorporation of Pyridine Rings

The synthesis of a series of triangular-shaped tricarboxamides endowed with three picoline or nicotine units (compounds 2 and 3, respectively) or just one nicotine unit (compound 4) is reported, and their self-assembling features investigated. The pyridine rings make compounds 2-4 electronically complementary with our previously reported oligo(phenylene ethynylene)tricarboxamides (OPE-TA) 1 to form supramolecular copolymers. C3 -symmetric tricarboxamide 2 forms highly stable intramolecular five-membered pseudocycles that impede its supramolecular polymerization into poly-2 and the co-assembly with 1 to yield copolymer poly-1-co-2. On the other hand, C3 -symmetric tricarboxamide 3 readily forms poly-3 with great stability but unable to form helical supramolecular polymers despite the presence of the peripheral chiral side chains. The copolymer poly-1-co-3 can only be obtained by a previous complete disassembly of the constitutive homopolymers in CHCl3 . Helical poly-1-co-3 arises in a process involving the transfer of the helicity from racemic poly-1 to poly-3, and the amplification of asymmetry from chiral poly-3 to poly-1. Importantly, C2v -symmetric 4, endowed with only one nicotinamide moiety and three chiral side chains, self-assembles into a P-type helical supramolecular polymer (poly-4) in a thermodynamically controlled cooperative process. The combination of poly-1 and poly-4 generates chiral supramolecular copolymer poly-1-co-4, whose blocky microstructure has been investigated by applying the previously reported supramolecular copolymerization model.

Pathway Control of π-Conjugated Supramolecular Polymers by Incorporating Donor-Acceptor Functionality

Controlling the nanoscale orientation of π-conjugated systems remains challenging due to the complexity of multiple energy landscapes involved in the supramolecular assembly process. In this study, we have developed an effective strategy for programming the pathways of π-conjugated supramolecular polymers, by incorporating both electron-rich methoxy- or methanthiol-benzene as donor unit and electron-poor cyano-vinylenes as acceptor units on the monomeric structure. It leads to the formation of parallel-stacked supramolecular polymers as the metastable species through homomeric donor/acceptor packing, which convert to slip-stacked supramolecular polymers as the thermodynamically stable species facilitated by heteromeric donor-acceptor packing. By further investigating the external seed-induced kinetic-to-thermodynamic transformation behaviors, our findings suggest that the donor-acceptor functionality on the seed structure is crucial for accelerating pathway conversion. This is achieved by eliminating the initial lag phase in the supramolecular polymerization process. Overall, this study provides valuable insights into designing molecular structures that control aggregation pathways of π-conjugated nanostructures.

Biomimetic Design of a Robustly Stabilized Folded State Enabling Seed-Initiated Supramolecular Polymerization under Microfluidic Mixing

We have investigated the folding and assembly behavior of a cystine-based dimeric diamide bearing pyrene units and solubilizing alkyl chains. In low-polarity solvents, it forms a 14-membered ring through double intramolecular hydrogen bonds between two diamide units. The spectroscopic studies revealed that the folded state is thermodynamically unstable and eventually transforms into more energetically stable helical supramolecular polymers that show an enhanced chiral excitonic coupling between the transition dipoles of the pyrene units. Importantly, compared to an alanine-based monomeric diamide, the dimeric diamide exhibits a superior kinetic stability in the metastable folded state, as well as an increased thermodynamic stability in the aggregated state. Accordingly, the initiation of supramolecular polymerization can be regulated using a seeding method even under microfluidic mixing conditions. Furthermore, taking advantage of a self-sorting behavior observed in a mixture of l-cysteine- and d-cysteine-based dimeric diamides, a two-step supramolecular polymerization was achieved by stepwise addition of the corresponding seeds.

Solvent-Induced Pathway Complexity of Supramolecular Polymerization Unveiled Using the Hansen Solubility Parameters

Supramolecular building blocks assembling into helical aggregates are ubiquitous in the current literature, yet the role of solvents in these supramolecular polymerizations often remains elusive. Here, we present a systematic study that quantifies solvent-supramolecular polymer compatibility using the Hansen solubility parameters (δD, δH, and δP). We first studied the solubility space of the supramolecular building block triazine-1,3,5-tribenzenecarboxamide S-T. Due to its amphiphilic nature, a dual-sphere model based on 58 solvents was applied describing the solubility space of the monomeric state (green sphere) and supramolecular polymer state (blue sphere). To our surprise, further in-depth spectroscopic and morphological studies unveiled a distinct solubility region in-between the two spheres giving rise to the formation of higher-order aggregated structures. This phenomenon occurs due to subtle differences in polarity between the solvent and the side chains and highlights the solvent-induced pathway complexity of supramolecular polymerizations. Subsequent variations in concentration and temperature led to the expansion and contraction of both solubility spheres providing two additional features to tune the monomer and supramolecular polymer solubility. Finally, we applied our dual-sphere model on structurally disparate monomers, such as Zn-porphyrin (S-P) and triphenylamine (S-A), demonstrating the generality of the model and the importance of the supramolecular monomer design in connection with the solvent used. This work unravels the solvent-induced pathway complexity of discotic supramolecular building blocks using a parametrized approach in which interactions between the solvent and solute play a crucial role.

Multistep, site-selective noncovalent synthesis of two-dimensional block supramolecular polymers

Although the principles of noncovalent bonding are well understood and form the basis for the syntheses of many intricate supramolecular structures, supramolecular noncovalent synthesis cannot yet achieve the levels of precision and complexity that are attainable in organic and/or macromolecular covalent synthesis. Here we show the stepwise synthesis of block supramolecular polymers from metal-porphyrin derivatives (in which the metal centre is Zn, Cu or Ni) functionalized with fluorinated alkyl chains. These monomers first undergo a one-dimensional supramolecular polymerization and cyclization process to form a toroidal structure. Subsequently, successive secondary nucleation, elongation and cyclization steps result in two-dimensional assemblies with concentric toroidal morphologies. The site selectivity endowed by the fluorinated chains, reminiscent of regioselectivity in covalent synthesis, enables the precise control of the compositions and sequences of the supramolecular structures, as demonstrated by the synthesis of several triblock supramolecular terpolymers.

Dynamic Control over Hierarchically Dendritic Architectures of Simple Heterogenous Monomers by Living Supramolecular Assembly

The successful preparation of supramolecular block copolymers (SBCPs) by living supramolecular assembly technology requires two kinetic systems in which both the seed (nucleus) and heterogenous monomer providers are in non-equilibrium. However, employing simple monomers to construct the SBCPs via this technology is almost impossible because the low spontaneous nucleation barrier of simple molecules prevents the formation of kinetic states. Here, with the help of confinement from layered double hydroxide (LDH), various simple monomers successfully form living supramolecular co-assemblies (LSCA). LDH overcomes a considerable energy barrier to obtain living seeds to support the growth of the inactivated second monomer. The ordered LDH topology is sequentially mapped to the seed, second monomer, and binding sites. Thus, the multidirectional binding sites are endowed with the ability to branch, making the branch length of dendritic LSCA reach its maximum value of 3.5 cm so far. The strategy of universality will guide exploration into the development of multi-function and multi-topology advanced supramolecular co-assemblies.

Pathway Complexity in Supramolecular Copolymerization and Blocky Star Copolymers by a Hetero-Seeding Effect

This study unravels the intricate kinetic and thermodynamic pathways involved in the supramolecular copolymerization of the two chiral dipolar naphthalene monoimide (NMI) building blocks (O-NMI and S-NMI), differing merely by a single heteroatom (oxygen vs sulfur). O-NMI exhibits distinct supramolecular polymerization features as compared to S-NMI in terms of its pathway complexity, hierarchical organization, and chiroptical properties. Two distinct self-assembly pathways in O-NMI occur due to the interplay between the competing dipolar interactions among the NMI chromophores and amide-amide hydrogen (H)-bonding that engenders distinct nanotapes and helical fibers, from its antiparallel and parallel stacking modes, respectively. In contrast, the propensity of S-NMI to form only a stable spherical assembly is ascribed to its much stronger amide-amide H-bonding, which outperforms other competing interactions. Under the thermodynamic route, an equimolar mixture of the two monomers generates a temporally controlled chiral statistical supramolecular copolymer that autocatalytically evolves from an initially formed metastable spherical heterostructure. In contrast, the sequence-controlled addition of the two monomers leads to the kinetically driven hetero-seeded block copolymerization. The ability to trap O-NMI in a metastable state allows its secondary nucleation from the surface of the thermodynamically stable S-NMI spherical "seed", which leads to the core-multiarmed "star" copolymer with reversibly and temporally controllable length of the growing O-NMI "arms" from the S-NMI "core". Unlike the one-dimensional self-assembly of O-NMI and its random co-assembly with S-NMI, which are both chiral, unprecedentedly, the preferred helical bias of the nucleating O-NMI fibers is completely inhibited by the absence of stereoregularity of the S-NMI "seed" in the "star" topology.

Porphyrin-based supramolecular polymers

Porphyrin derivatives are ubiquitous in bio-organisms and are associated with proteins that play important biological roles, such as oxygen transport, photosynthesis, and catalysis. Porphyrins are very fascinating research objects for chemists, physicists, and biologists owing to their versatile chemical and physical properties. Porphyrin derivatives are actively used in various fields, such as molecular recognition, energy conversion, sensors, biomedicine, and catalysts. Porphyrin derivatives can be used as building blocks for supramolecular polymers because their primitive structures have C₄ symmetry, which allows for the symmetrical introduction of self-assembling motifs. This review describes the fabrication of porphyrin-based supramolecular polymers and novel discoveries in supramolecular polymer growth. First, we summarise the (i) design concepts, (ii) growth mechanism and (iii) analytical methods of porphyrin-based supramolecular polymers. Then, the examples of porphyrin-based supramolecular polymers formed by (iv) hydrogen bonding, (v) metal coordination-based interaction, (vi) host-guest complex formation, and (vii) others are summarised. Finally, (viii) applications and perspectives are discussed. Although supramolecular polymers, in a broad sense, can include either two-dimensional (2D) networks or three-dimensional (3D) porous polymer structures; this review mainly focuses on one-dimensional (1D) fibrous supramolecular polymer structures.

Pillararene-Based Supramolecular Polymers for Cancer Therapy

Supramolecular polymers have attracted considerable interest due to their intriguing features and functions. The dynamic reversibility of noncovalent interactions endows supramolecular polymers with tunable physicochemical properties, self-healing, and externally stimulated responses. Among them, pillararene-based supramolecular polymers show great potential for biomedical applications due to their fascinating host-guest interactions and easy modification. Herein, we summarize the state of the art of pillararene-based supramolecular polymers for cancer therapy and illustrate its developmental trend and future perspective.

Individually separated supramolecular polymer chains toward solution-processable supramolecular polymeric materials

Herein, we present a simple design concept for a monomer that affords individually separated supramolecular polymer chains. Random introduction of alkyl chains with different lengths onto a monomer prevented its supramolecular polymers from bundling, permitting the preparation of concentrated solutions of the supramolecular polymer without gelation, precipitation, or crystallization. With such a solution in hand, we succeeded in fabricating self-standing films and threads consisting of supramolecular polymers.

Controlled Supramolecular Self-Assembly Pathways by Intramolecular Rotation of D-A Molecular System toward the Signal Differentiation Detection of Toxic Vapors

Revealing the structural evolution mechanisms of supramolecular self-assembly can facilitate the exploitation of new self-assembly pathways and various functional materials. Here, this work reports a unique intramolecular rotation-induced structural evolution of supramolecular assemblies from a metastable state to a thermodynamically stable state using a twisting D-A molecule. These self-assemblies are applied to the signal differentiation detection of toxic dimethylsulfide (DMS) vapors. The F₁₆₁ BT monomer of the inactive state is trapped in off-pathway metastable nanospheres, which can disassemble and induce the transformation of the F₁₆₁ BT monomer into an active state by crossing the energy barrier. Subsequently, the active monomer goes through the processes of nucleation and elongation, forming thermodynamically stable on-pathway microribbons. Adding seeds can accelerate the molecular conformational transformation, generating microribbons with controlled lengths. Opposite fluorescent responses are obtained when exposing the two aggregates to the DMS vapors, allowing the sensitive detection of DMS with enhanced selectivity, which offers tremendous potential in practical applications.

Modular Platform of Carbohydrates-modified Supramolecular Polymers Based on Dendritic Peptide Scaffolds

Glycopeptide supramolecular polymers displaying multivalent carbohydrates are particularly suitable for immune-relevant biomaterials, due to the important functions of carbohydrates in mediating cell-cell communication and modulating immune responses. However, the diversity and complexity of carbohydrates limited the generation of glycopeptide supramolecular monomers. Thereby, a modular platform of presenting various carbohydrates, especially more complex oligosaccharides, is highly desirable but remains underexplored. Here, we first prepared the linear amphiphilic glycopeptides that self-assembled into spherical nanoparticles and worm-like nanoparticles. Furthermore, the dendritic glycopeptides that self-assembled into uniform nanorods were designed to generate modular supramolecular polymers with variable functionality, via redesigning the molecular backbone. With various functional oligosaccharide-modified supramolecular polymers, the in vitro studies further indicated that these polymers were not cytotoxic to macrophages, and significantly modulated the production of proinflammatory cytokines. These findings provide a promising platform to develop supramolecular glycopeptide biomaterials with potential applications in immunomodulation and immunotherapy.

Kinetically Programming Copolymerization-like Coassembly of Multicomponent Nanoparticles with DNA

Programmable coassembly of multicomponent nanoparticles (NPs) into heterostructures has the capability to build upon nanostructured metamaterials with enhanced complexity and diversity. However, a general understanding of how to manipulate the sequence-defined heterostructures using straightforward concepts and quantitatively predict the coassembly process remains unreached. Drawing inspiration from the synthetic concepts of molecular block copolymers is extremely beneficial to achieve controllable coassembly of NPs and access mesoscale structuring mechanisms. We herein report a general paradigm of kinetic pathway guidance for the controllable coassembly of bivalent DNA-functionalized NPs into regular block-copolymer-like heterostructures via the stepwise polymerization strategy. By quantifying the coassembly kinetics and structural statistics, it is demonstrated that the coassembly of multicomponent NPs, through directing the specific pathways of prepolymer intermediates, follows the step-growth copolymerization mechanism. Meanwhile, a quantitative model is developed to predict the growth kinetics and outcomes of heterostructures, all controlled by the designed elements of the coassembly system. Furthermore, the stepwise polymerization strategy can be generalized to build upon a great variety of regular nanopolymers with complex architectures, such as multiblock terpolymers and ladder copolymers. Our theoretical and simulation results provide fundamental insights on quantitative predictions of the coassembly kinetics and coassembled outcomes, which can aid in realizing a diverse set of supramolecular DNA materials by the rational design of kinetic pathways.

Hierarchically supramolecular polymerization of anthraquinone dye to chiral aggregates via 2D-monolayered nanosheets: the unanticipated role of pathway complexity

An anthraquinone dye underwent supramolecular polymerization, affording 2D-monolayered nanosheets in a kinetically controlled state. The nanosheets then transformed into hierarchically chiral aggregates in a thermodynamically controlled step. The unanticipated role played by pathway complexity was clearly unravelled in this work, highlighting the diversified pathways in the supramolecular polymerization of various building blocks.

Secondary Nucleation-Triggered Physical Cross-Links and Tunable Stiffness in Seeded Supramolecular Hydrogels

Mechanistic understanding and the control of molecular self-assembly at all hierarchical levels remain grand challenges in supramolecular chemistry. Functional realization of dynamic supramolecular materials especially requires programmed assembly at higher levels of molecular organization. Herein, we report an unprecedented molecular control on the fibrous network topology of supramolecular hydrogels and their resulting macroscopic properties by biasing assembly pathways of higher-order structures. The surface-catalyzed secondary nucleation process, a well-known mechanism in amyloid fibrilization and chiral crystallization of small molecules, is introduced as a non-covalent strategy to induce physical cross-links and bundling of supramolecular fibers, which influences the microstructure of gel networks and subsequent mechanical properties of hydrogels. In addition, seed-induced instantaneous gelation is realized in the kinetically controlled self-assembled system under this study, and more importantly, the extent of secondary nucleation events and network topology is manipulated by the concentration of seeds.

Chirality-Controlled Supramolecular Donor-Acceptor Copolymerization with Distinct Energy Transfer Efficiency

Chirality delivers substantial value to the field of supramolecular polymers, not only serving as a probe to monitor the dynamic assembly process but providing access to chiroptical materials. The current study demonstrates that, for supramolecular donor-acceptor copolymers, their comonomer organization modes can be greatly influenced by stereocommunication at the molecular level. The enantiopure N-[(1R or 1S)-phenylethyl]benzamides are incorporated into two structurally similar comonomers, locating between the π-aromatic diethynylacene core and the alkyl chain peripheries. Parallel arrangement of the stereogenic methyl units brings steric hindrance between the homochiral comonomers, which is relieved for the heterochiral comonomers due to the adoption of staggered arrangement. It consequently steers randomly mixed organization for the homochiral supramolecular copolymers within the nanofibers. In comparison, the heterochiral counterparts form nanoparticles in an alternate donor-acceptor organization manner. The variation of comonomer arrangement modes gives rise to distinct energy transfer efficiency at the supramolecular level. Overall, the elaborate manipulation of stereogenic centers in the comonomer structures exerts significant impacts on the characteristics of supramolecular copolymers, which could be useful for chiral sensing, recognition, and optoelectronic applications.

Molecular communications in complex systems of dynamic supramolecular polymers

Supramolecular polymers are composed of monomers that self-assemble non-covalently, generating distributions of monodimensional fibres in continuous communication with each other and with the surrounding solution. Fibres, exchanging molecular species, and external environment constitute a sole complex system, which intrinsic dynamics is hard to elucidate. Here we report coarse-grained molecular simulations that allow studying supramolecular polymers at the thermodynamic equilibrium, explicitly showing the complex nature of these systems, which are composed of exquisitely dynamic molecular entities. Detailed studies of molecular exchange provide insights into key factors controlling how assemblies communicate with each other, defining the equilibrium dynamics of the system. Using minimalistic and finer chemically relevant molecular models, we observe that a rich concerted complexity is intrinsic in such self-assembling systems. This offers a new dynamic and probabilistic (rather than structural) picture of supramolecular polymer systems, where the travelling molecular species continuously shape the assemblies that statistically emerge at the equilibrium.

The dynamic structure of supramolecular polymers is challenging to determine both in experiments and in simulations. Here the authors use coarse-grained molecular models to provide a comprehensive analysis of the molecular communication in these complex molecular systems.

Co-assembly of a multicomponent network of nanofiber-wrapped nanotubes

Strategies to create organized multicomponent nanostructures composed of discrete, self-sorted domains are important for developing materials that mimic the complexity and multifunctionality found in biological systems. These structures can be challenging to achieve due to the required balance of molecular self-recognition and supramolecular attraction needed between the components. Herein, we report a strategy to construct a two-component nanostructure via a hierarchical assembly process whereby two monomeric building blocks undergo self-sorting assembly at the molecular level followed by a supramolecular association to form a nanofiber-wrapped nanotube. The two molecules self-sorted into respective nanofiber and nanotube assemblies, yet assembly of the nanofibers in the presence of the nanotube template allowed for directed integration into a hierarchical multilayer structure via electrostatic interactions. The fiber-wrapped nanotube co-assembly was characterized using transmission electron microscopy (TEM), atomic force microscopy (AFM) and Förster resonance energy transfer (FRET) between the components. Strategies to co-assemble multicomponent nanostructures composed of discrete, spatially sorted domains with controllable higher level interactions will be critical for the development of novel, functionally competent nanomaterials.

Synthesis and Self-assembly of Benzoperylene Benzimidazoles: Tunable Morphology with Aggregation Induced Enhanced Emission

Benzoperylene benzimidazoles ( BPBIs ) based π-systems are synthesized and their self-assembly in both non-polar and polar solvents is investigated. Due to the presence of donor and acceptor functional groups,  BPBIs  absorb light up to 600 nm and display red fluorescence (575-800 nm). Depending on the solvent and side chain,  BPBIs  self-assemble into various nanostructures such as nanoribbons, nanorods, nanofibers and nanoparticles. Notably, these ordered nanostructures are formed by  BPBIs  in both polar and non-polar solvents   without the aid of hydrogen bonding and amphiphilic interactions due to the presence of a large rigid π-system. Interestingly,  BPBIs  follow a weakly cooperative mechanism during the self-assembly. Moreover,  BPBIs  show aggregation induced enhanced emission (AIEE) in all the self-assembled nanostructures which is not common for rigid π-systems.

Hierarchical self-assembly of aromatic peptide conjugates into supramolecular polymers: it takes two to tango

Supramolecular polymers are self-assembled materials displaying adaptive and responsive "life-like" behaviour which are often made of aromatic compounds capable of engaging in π-π interactions to form larger assemblies. Major advances have been made recently in controlling their mode of self-assembly, from thermodynamically-controlled isodesmic to kinetically-controlled living polymerization. Dynamic covalent chemistry has been recently implemented to generate dynamic covalent polymers which can be seen as dynamic analogues of biomacromolecules. On the other hand, peptides are readily-available and structurally-rich building blocks that can lead to secondary structures or specific functions. In this context, the past decade has seen intense research activity in studying the behaviour of aromatic-peptide conjugates through supramolecular and/or dynamic covalent chemistries. Herein, we review those impressive key achievements showcasing how aromatic- and peptide-based self-assemblies can be combined using dynamic covalent and/or supramolecular chemistry, and what it brings in terms of the structure, self-assembly pathways, and function of supramolecular and dynamic covalent polymers.

Controlling the length of porphyrin supramolecular polymers via coupled equilibria and dilution-induced supramolecular polymerization

Multi-component systems often display convoluted behavior, pathway complexity and coupled equilibria. In recent years, several ways to control complex systems by manipulating the subtle balances of interaction energies between the individual components have been explored and thereby shifting the equilibrium between different aggregate states. Here we show the enantioselective chain-capping and dilution-induced supramolecular polymerization with a Zn²⁺-porphyrin-based supramolecular system when going from long, highly cooperative supramolecular polymers to short, disordered aggregates by adding a monotopic Mn³⁺-porphyrin monomer. When mixing the zinc and manganese centered monomers, the Mn³⁺-porphyrins act as chain-cappers for Zn²⁺-porphyrin supramolecular polymers, effectively hindering growth of the copolymer and reducing the length. Upon dilution, the interaction between chain-capper and monomers weakens as the equilibria shift and long supramolecular polymers form again. This dynamic modulation of aggregate morphology and length is achieved through enantioselectivity in the aggregation pathways and concentration-sensitive equilibria. All-atom and coarse-grained molecular simulations provide further insights into the mixing of the species and their exchange dynamics. Our combined experimental and theoretical approach allows for precise control of molecular self-assembly and chiral discrimination in complex systems.

Elucidating the Supramolecular Copolymerization of N- and C-Centered Benzene-1,3,5-Tricarboxamides: The Role of Parallel and Antiparallel Packing of Amide Groups in the Copolymer Microstructure

An in-depth study of the supramolecular copolymerization behavior of N- and C-centered benzene-1,3,5-tricarboxamides (N- and C-BTAs) has been conducted in methylcyclohexane and in the solid state. The connectivity of the amide groups in the BTAs differs, and mixing N- and C-BTAs results in supramolecular copolymers with a blocky microstructure in solution. The blocky microstructure results from the formation of weaker and less organized, antiparallel hydrogen bonds between N- and C-BTAs. In methylcyclohexane, the helical threefold hydrogen-bonding network present in C- and N-BTAs is retained in the mixtures. In the solid state, in contrast, the hydrogen bonds of pure BTAs as well as their mixtures organize in a sheet-like pattern, and in the mixtures long-range order is lost. Drop-casting to kinetically trap the solution microstructures shows that C-BTAs retain the helical hydrogen bonds, but N-BTAs immediately adopt the sheet-like pattern, a direct consequence of the lower stabilization energy of the helical hydrogen bonds. In the copolymers, the stability of the helical aggregates depends on the copolymer composition, and helical aggregates are only preserved when a high amount of C-BTAs is present. The method outlined here is generally applicable to elucidate the copolymerization behavior of supramolecular monomers both in solution as well as in the solid state.

Helicity-driven chiral self-sorting supramolecular polymerization with Ag+: right- and left-helical aggregates

The study of chiral self-sorting is extremely important for understanding biological systems and for developing applications for the biomedical field. In this study, we attempted an unprecedented chiral self-sorting supramolecular...

Supramolecular polymerization of electronically complementary linear motifs: anti-cooperativity by attenuated growth

Anti-cooperative supramolecular polymerization by attenuated growth exhibited by self-assembling units of two electron-donor benzo[1,2-b:4,5-b']dithiophene (BDT) derivatives (compounds 1a and 1b) and the electron-acceptor 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) (compound 2) is reported. Despite the apparent cooperative mechanism of 1 and 2, AFM imaging and SAXS measurements reveal the formation of small aggregates that suggest the operation of an anti-cooperative mechanism strongly conditioned by an attenuated growth. In this mechanism, the formation of the nuclei is favoured over the subsequent addition of monomeric units to the aggregate, which finally results in short aggregates. Theoretical calculations show that both the BDT and BODIPY motifs, after forming the initial dimeric nuclei, experience a strong distortion of the central aromatic backbone upon growth, which makes the addition of successive monomeric units unfavourable and impedes the formation of long fibrillar structures. Despite the anti-cooperativity observed in the supramolecular polymerization of 1 and 2, the combination of both self-assembling units results in the formation of small co-assembled aggregates with a similar supramolecular polymerization behaviour to that observed for the separate components.

Non-uniform Photoinduced Unfolding of Supramolecular Polymers Leading to Topological Block Nanofibers

Synthesis of one-dimensional nanofibers with distinct topological (higher-order structural) domains in the same main chain is one of the challenging topics in modern supramolecular polymer chemistry. Non-uniform structural transformation of supramolecular polymer chains by external stimuli may enable preparation of such nanofibers. To demonstrate feasibility of this post-polymerization strategy, we prepared a photoresponsive helically folded supramolecular polymers from a barbiturate monomer containing an azobenzene-embedded rigid π-conjugated scaffold. In contrast to previous helically folded supramolecular polymers composed of a more flexible azobenzene monomer, UV-light induced unfolding of the newly prepared helically folded supramolecular polymers occurred nonuniformly, affording topological block copolymers consisting of folded and unfolded domains. The formation of such blocky copolymers indicates that the photoinduced unfolding of the helically folded structures initiates from relatively flexible parts such as termini or defects. Spontaneous refolding of the unfolded domains was observed after visible-light irradiation followed by aging to restore fully folded structures.