From isodesmic to highly cooperative: reverting the supramolecular polymerization mechanism in water by fine monomer design

Bisurea-Based Supramolecular Polymers for Tunable Biomaterials

Water-soluble supramolecular polymers show great potential to develop dynamic biomaterials with tailored properties. Here, we elucidate the morphology, stability and dynamicity of supramolecular polymers derived from bisurea-based monomers. An accessible synthetic approach from 2,4-toluene diisocyanate (TDI) as the starting material is developed. TDI has two isocyanates that differ in intrinsic reactivity, which allows to obtain functional, desymmetrized monomers in a one-step procedure. We explore how the hydrophobic/hydrophilic ratio affects the properties of the formed supramolecular polymers by increasing the number of methylene units from 10 to 12 keeping the hydrophilic hexa(ethylene glycol) constant. All bisurea-based monomers form long, fibrous structures with 3-5 monomers in the cross-section in water, indicating a proper hydrophobic\hydrophilic balance. The stability of the supramolecular polymers increases with an increasing amount of methylene units, whereas the dynamic nature of the monomers decreases. The introduction of one Cy3 dye affords modified supramolecular monomers, which co-assemble with the unmodified monomers into fibrous structures. All systems show excellent water-compatibility and no toxicity for different cell-lines. Importantly, in cell culture media, the fibrous structures remain present, highlighting the stability of these supramolecular polymers in physiological conditions. The results obtained here motivate further investigation of these bisurea-based building blocks as dynamic biomaterial.

Entropy-Enthalpy Compensation in Solvent Geometry Regulated Supramolecular Polymerization of Luminescent Napthalimide via a Non-Cooperative, Isodesmic Mechanism

Supramolecular polymers of π-conjugated systems are an important class of materials with fascinating functions and properties originated from the dynamic behavior and highly ordered molecular organizations. Here, a donor-π-acceptor based functionalized luminescent napthalene monoimide (NMI) undergoes J-type self-assembly by non-covalent interactions via a non-cooperative, isodesmic mechanism to form supramolecular 1D nanowire. The fundamental insights into the thermodynamics regulating the supramolecular polymerization were derived through the fitting of the isodesmic model to variable temperature UV/Vis data in linear (dodecane) and nonliner hydrocarbon (decalin) based solvents. This shows a significant role of entropy-enthalpy compensation in solvent geometry-regulated formation and stabilization of supramolecular polymer. Furthermore, we have quantitively estimated the influence of solvent geometry and found that NMI forms stronger self-assembly and spontaneous gel in linear hydrocarbon based solvent compared to nonliner one and thereby substantially increases the degree of polymerization in linear hydrocarbon solvent (dodecane). This is accredited to the effective influence of the linear hydrocarbon solvent molecules in the polymerization process by favourable van der waals interactions with the peripheral alkyl chains of the NMI monomers in contrast to unfavourable interaction of nonliner hydrocarbon solvent due to geometry mismatch.

pH- and temperature-responsive supramolecular assemblies with highly adjustable viscoelasticity: a multi-stimuli binary system

Stimuli-responsive materials are increasingly needed for the development of smart electronic, mechanical, and biological devices and systems relying on switchable, tunable, and adaptable properties. Herein, we report a novel pH- and temperature-responsive binary supramolecular assembly involving a long-chain hydroxyamino amide (HAA) and an inorganic hydrotrope, boric acid, with highly tunable viscous and viscoelastic properties. The system under investigation demonstrates a high degree of control over its viscosity, with the capacity to achieve over four orders of magnitude of control through the concomitant manipulation of pH and temperature. In addition, the transformation from non-Maxwellian to Maxwellian fluid behavior could also be induced by changing the pH and temperature. Switchable rheological properties were ascribed to the morphological transformation between spherical vesicles, aggregated/fused spherical vesicles, and bicontinuous gyroid structures revealed by cryo-TEM studies. The observed transitions are attributed to the modulation of the head group spacing between HAA molecules under different pH conditions. Specifically, acidic conditions induce electrostatic repulsion between the protonated amino head groups, leading to an increased spacing. Conversely, under basic conditions, the HAA head group spacing is reduced due to the intercalation of tetrahydroxyborate, facilitated by hydrogen bonding.

Density-tunable pathway complexity in a minimalistic self-assembly model

An open challenge in self-assembly is learning how to design systems that can be conditionally guided towards different target structures depending on externally-controlled conditions. Using a theoretical and numerical approach, here we discuss a minimalistic self-assembly model that can be steered towards different types of ordered constructs at the equilibrium by solely tuning a facile selection parameter, namely the density of building blocks. Metadynamics and Langevin dynamics simulations allow us to explore the behavior of the system in and out of equilibrium conditions. We show that the density-driven tunability is encoded in the pathway complexity of the system, and specifically in the competition between two different main self-assembly routes. A comprehensive set of simulations provides insight into key factors allowing to make one self-assembling pathway prevailing on the other (or vice versa), determining the selection of the final self-assembled products. We formulate and validate a practical criterion for checking whether a specific molecular design is predisposed for such density-driven tunability of the products, thus offering a new, broader perspective to realize and harness this facile extrinsic control of conditional self-assembly.

Classifying soft self-assembled materials via unsupervised machine learning of defects

Unlike molecular crystals, soft self-assembled fibers, micelles, vesicles, etc., exhibit a certain order in the arrangement of their constitutive monomers but also high structural dynamicity and variability. Defects and disordered local domains that continuously form-and-repair in their structures impart to such materials unique adaptive and dynamical properties, which make them, e.g., capable to communicate with each other. However, objective criteria to compare such complex dynamical features and to classify soft supramolecular materials are non-trivial to attain. Here we show a data-driven workflow allowing us to achieve this goal. Building on unsupervised clustering of Smooth Overlap of Atomic Position (SOAP) data obtained from equilibrium molecular dynamics simulations, we can compare a variety of soft supramolecular assemblies via a robust SOAP metric. This provides us with a data-driven "defectometer" to classify different types of supramolecular materials based on the structural dynamics of the ordered/disordered local molecular environments that statistically emerge within them.

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.

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.

Porphyrin-based supramolecular nanofibres as a dynamic and activatable photosensitiser for photodynamic therapy

Photodynamic therapy (PDT) represents a promising treatment modality for a range of cancers and other non-malignant diseases due to its non-invasive nature arising from the light-dependent activation. However, PDT has...

Controlling Exchange Pathways in Dynamic Supramolecular Polymers by Controlling Defects

Supramolecular fibers composed of monomers that self-assemble directionally via noncovalent interactions are ubiquitous in nature, and of great interest in chemistry. In these structures, the constitutive monomers continuously exchange in-and-out the assembly according to a well-defined supramolecular equilibrium. However, unraveling the exchange pathways and their molecular determinants constitutes a nontrivial challenge. Here, we combine coarse-grained modeling, enhanced sampling, and machine learning to investigate the key factors controlling the monomer exchange pathways in synthetic supramolecular polymers having an intrinsic dynamic behavior. We demonstrate how the competition of directional vs. nondirectional interactions between the monomers controls the creation/annihilation of defects in the supramolecular polymers, from where monomers exchange proceeds. This competition determines the exchange pathway, dictating whether a fiber statistically swaps monomers from the tips or from all along its length. Finally, thanks to their generality, our models allow the investigation of molecular approaches to control the exchange pathways in these dynamic assemblies.

Unveiling Polymerization Mechanism in pH-regulated Supramolecular Fibers in Aqueous Media

An amine functionalized C₃‐symmetric benzotrithiophene (BTT) monomer has been designed and synthetized in order to form pH responsive one‐dimensional supramolecular polymers in aqueous media. While most of the reported studies looked at the effect of pH on the size of the aggregates, herein, a detailed mechanistic study is reported, carried out upon modifying the pH to trigger the formation of positively charged ammonium groups. A dramatic and reversible change in the polymerization mechanism and size of the supramolecular fibers is observed and ascribed to the combination of Coulombic repulsive forces and higher monomer solubility. Furthermore, the induced frustrated growth of the fibers is further employed to finely control the one‐dimensional supramolecular polymerisation and copolymerization processes.

Elucidating dynamic behavior of synthetic supramolecular polymers in water by hydrogen/deuterium exchange mass spectrometry

A comprehensive understanding of the structure, self-assembly mechanism, and dynamics of one-dimensional supramolecular polymers in water is essential for their application as biomaterials. Although a plethora of techniques are available to study the first two properties, there is a paucity in possibilities to study dynamic exchange of monomers between supramolecular polymers in solution. We recently introduced hydrogen/deuterium exchange mass spectrometry (HDX-MS) to characterize the dynamic nature of synthetic supramolecular polymers with only a minimal perturbation of the chemical structure. To further expand the application of this powerful technique some essential experimental aspects have been reaffirmed and the technique has been applied to a diverse library of assemblies. HDX-MS is widely applicable if there are exchangeable hydrogen atoms protected from direct contact with the solvent and if the monomer concentration is sufficiently high to ensure the presence of supramolecular polymers during dilution. In addition, we demonstrate that the kinetic behavior as probed by HDX-MS is influenced by the internal order within the supramolecular polymers and by the self-assembly mechanism.

The Martini Model in Materials Science

The Martini model, a coarse-grained force field initially developed with biomolecular simulations in mind, has found an increasing number of applications in the field of soft materials science. The model's underlying building block principle does not pose restrictions on its application beyond biomolecular systems. Here, the main applications to date of the Martini model in materials science are highlighted, and a perspective for the future developments in this field is given, particularly in light of recent developments such as the new version of the model, Martini 3.

Tuning the mechanistic pathways of peptide self-assembly by aromatic interactions

Herein, we have unravelled the key influence of aromatic interactions on the mechanistic pathways of peptide self-assembly by introducing suitable chromophores (pyrene vs. naphthalene). Although both self-assembled peptides are indistinguishable in their morphologies, this minor structural difference strongly affects the packing modes (parallel vs. antiparallel) and the corresponding self-assembly mechanism (cooperative vs. isodemsic).

Exploring the tubular self-assembly landscape of dinucleobase amphiphiles in water

The tubular aqueous assembly of dinucleobase amphiphilic monomers endowed with anionic, neutral or cationic groups is investigated under diverse conditions.

Swarm-CG: Automatic Parametrization of Bonded Terms in MARTINI-Based Coarse-Grained Models of Simple to Complex Molecules via Fuzzy Self-Tuning Particle Swarm Optimization

We present Swarm-CG, a versatile software for the automatic iterative parametrization of bonded parameters in coarse-grained (CG) models, ideal in combination with popular CG force fields such as MARTINI. By coupling fuzzy self-tuning particle swarm optimization to Boltzmann inversion, Swarm-CG performs accurate bottom-up parametrization of bonded terms in CG models composed of up to 200 pseudo atoms within 4-24 h on standard desktop machines, using default settings. The software benefits from a user-friendly interface and two different usage modes (default and advanced). We particularly expect Swarm-CG to support and facilitate the development of new CG models for the study of complex molecular systems interesting for bio- and nanotechnology. Excellent performances are demonstrated using a benchmark of 9 molecules of diverse nature, structural complexity, and size. Swarm-CG is available with all its dependencies via the Python Package Index (PIP package: swarm-cg). Demonstration data are available at: www.github.com/GMPavanLab/SwarmCG.

Solute-Solvent Interactions in Modern Physical Organic Chemistry: Supramolecular Polymers as a Muse

Interactions between solvents and solutes are a cornerstone of physical organic chemistry and have been the subject of investigations over the last century. In recent years, a renewed interest in fundamental aspects of solute-solvent interactions has been sparked in the field of supramolecular chemistry in general and that of supramolecular polymers in particular. Although solvent effects in supramolecular chemistry have been recognized for a long time, the unique opportunities that supramolecular polymers offer to gain insight into solute-solvent interactions have become clear relatively recently. The multiple interactions that hold the supramolecular polymeric structure together are similar in strength to those between solute and solvent. The cooperativity found in ordered supramolecular polymers leads to the possibility of amplifying these solute-solvent effects and will shed light on extremely subtle solvation phenomena. As a result, many exciting effects of solute-solvent interactions in modern physical organic chemistry can be studied using supramolecular polymers. Our aim is to put the recent progress into a historical context and provide avenues toward a more comprehensive understanding of solvents in multicomponent supramolecular systems.

Solvent-driven chirality for luminescent self-assembled structures: experiments and theory

We describe, for a single platinum complex bearing a dipeptide moiety, a solvent-driven interconversion from twisted to straight micrometric assembled structures with different chirality. The photophysical and morphological properties of the aggregates have been investigated as well as the role of the media and concentration. A real-time visualization of the solvent-driven interconversion processes has been achieved by confocal microscopy. Finally, atomistic and coarse-grained simulations, providing results consistent with the experimental observations, allow to obtain a molecular-level insight into the interesting solvent-responsive behavior of this system.

How Water in Aliphatic Solvents Directs the Interference of Chemical Reactivity in a Supramolecular System

Water is typically considered to be insoluble in alkanes. Recently, however, monomerically dissolved water in alkanes has been shown to dramatically impact the structure of hydrogen-bonded supramolecular polymers. Here, we report that water in methylcyclohexane (MCH) also determines the outcome of combining a Michael reaction with a porphyrin-based supramolecular system. In dry conditions, the components of the reaction do not affect or destabilize the supramolecular polymer, whereas in ambient or wet conditions the polymers are rapidly destabilized. Although spectroscopic investigations show no effect of water on the molecular structure of the supramolecular polymer, light scattering and atomic force microscopy experiments show that water increases the flexibility of the supramolecular polymer and decreases the polymer length. Through a series of titrations, we show that a cooperative interaction, involving the coordination of the amine catalyst to the porphyrin and complexation of the substrates to the flexible polymers invokes the depolymerization of the aggregates. Water crucially stabilizes these cooperative interactions to cause complete depolymerization in humid conditions. Additionally, we show that the humidity-controlled interference in the polymer stability occurs with various substrates, indicating that water may play a ubiquitous role in supramolecular polymerizations in oils. By controlling the amount of water, the influence of a covalent chemical process on noncovalent aggregates can be mediated, which holds great potential to forge a connection between chemical reactivity and supramolecular material structure. Moreover, our findings highlight that understanding cooperative interactions in multicomponent noncovalent systems is crucial to design complex molecular systems.

An Azobenzene-Based Single-Component Supramolecular Polymer Responsive to Multiple Stimuli in Water

One of the most appealing features of supramolecular assemblies is their ability to respond to external stimuli due to their noncovalent nature. This provides the opportunity to gain control over their size, morphology, and chemical properties and is key toward some of their applications. However, the design of supramolecular systems able to respond to multiple stimuli in a controlled fashion is still challenging. Here we report the synthesis and characterization of a novel discotic molecule, which self-assembles in water into a single-component supramolecular polymer that responds to multiple independent stimuli. The building block of such an assembly is a C₃-symmetric monomer, consisting of a benzene-1,3,5-tricarboxamide core conjugated to a series of natural and non-natural functional amino acids. This design allows the use of rapid and efficient solid-phase synthesis methods and the modular implementation of different functionalities. The discotic monomer incorporates a hydrophobic azobenzene moiety, an octaethylene glycol chain, and a C-terminal lysine. Each of these blocks was chosen for two reasons: to drive the self-assembly in water by a combination of H-bonding and hydrophobicity and to impart specific responsiveness. With a combination of microscopy and spectroscopy techniques, we demonstrate self-assembly in water and responsiveness to temperature, light, pH, and ionic strength. This work shows the potential to integrate independent mechanisms for controlling self-assembly in a single-component supramolecular polymer by the rational monomer design and paves the way toward the use of multiresponsive systems in water.

pH-Responsive Side Chains as a Tool to Control Aqueous Self-Assembly Mechanisms

pH-Tunable nanoscale morphology and self-assembly mechanism of a series of oligo(p-phenyleneethynylene) (OPE)-based bolaamphiphiles featuring poly(ethylene imine) (PEI) side chains of different length and degree of hydrolysis are described. Protonation and deprotonation of the PEI chains by changing the pH alters the hydrophilic/hydrophobic balance of the systems and, in turn, the strength of intermolecular interactions between the hydrophobic OPE moieties. Low pH values (3) lead to weak interaction between the OPEs and result in spherical nanoparticles, in which aggregation follows an isodesmic mechanism. In contrast, higher pH values (11) induce deprotonation of the polymer chains and lead to a stronger, cooperative aggregation into anisotropic nanostructures. Our results demonstrate that pH-responsive chains can be exploited as a tool to tune self-assembly mechanisms, which opens exciting possibilities to develop new stimuli-responsive materials.

Mass-Balance Models for Scrutinizing Supramolecular (Co)polymerizations in Thermodynamic Equilibrium

Recent years have witnessed increasing attention on supramolecular polymerization, i.e., the formation of one-dimensional aggregates in which the monomeric units bind together via reversible and usually highly directional non-covalent interactions. Because of the presence of these reversible interactions, such as hydrogen bonding, π-π interactions, or metal coordination, supramolecular polymers exhibit numerous desirable properties ranging from high thermoresponsiveness to self-healing and great capacity for processability and recycling. These properties relate to intriguing experimentally observed nonlinear effects such as the monomer-dependent presence of a critical temperature for aggregation and a solvent- and temperature-tunable aggregate morphology. For coassemblies this is complemented with monomer-ratio- and monomer-compatibility-dependent internal order as well as majority-rules-type chiral amplification. However, the dynamic nature of the (co)polymers and the intricate interplay of many interactions make these effects difficult to rationalize without theoretical models. This Account presents recent advances in the development and use of equilibrium models for supramolecular copolymerization based on mass balances, mainly developed by our group. The basic idea of these models is that we describe a supramolecular (co)polymerization by a set of independent equilibrium reactions, like monomer associations and dissociations, and that in thermodynamic equilibrium the concentrations of the reactants and products in each reaction are coupled via the equilibrium constant of that reaction. Recursion then allows the concentration of each possible aggregate to be written as a function of the free monomer concentrations. Because a monomer should be present either as a free monomer or in one of the aggregates, a set of n equations can be formed with the n free monomer concentrations as the only unknowns. This set of mass-balance equations can then be solved numerically, yielding the free monomer concentrations, from which the complete system can be reconstituted. By a step-by-step extension of the model for the aggregation of a single monomer type to include the formation of multiple aggregate types and the coassembly of multiple monomer types, we can capture increasingly complex supramolecular (co)polymerizations. In each step we illustrate how the extended model explains in detail another of the experimentally observed nonlinear effects, with the common denominator that small differences in association energies are intricately amplified at the supramolecular level. We finally arrive at our latest and most general approach to modeling (cooperative) supramolecular (co)polymerization, which encompasses all of our earlier models and shows great promise to help rationalize also future systems featuring ever-increasing complexity.

Detailed Approach to Investigate Thermodynamically Controlled Supramolecular Copolymerizations

Elucidating the microstructure of supramolecular copolymers remains challenging, despite the progress in the field of supramolecular polymers. In this work, we present a detailed approach to investigate supramolecular copolymerizations under thermodynamic control. Our approach provides insight into the interactions of different types of monomers and hereby allows elucidating the microstructure of copolymers. We select two monomers that undergo cooperative supramolecular polymerization by way of threefold intermolecular hydrogen bonding in a helical manner, namely, benzene-1,3,5-tricarboxamide (BTA) and benzene-1,3,5-tris(carbothioamide) (thioBTA). Two enantiomeric forms and an achiral analogue of BTA and thioBTA are synthesized and their homo- and copolymerizations are studied using light scattering techniques, infrared, ultraviolet, and circular dichroism spectroscopy. After quantifying the thermodynamic parameters describing the homopolymerizations, we outline a method to follow the self-assembly of thioBTA derivatives in the copolymerization with BTA, which involves monitoring a characteristic spectroscopic signature as a function of temperature and relative concentration. Using modified types of sergeants-and-soldiers and majority-rules experiments, we obtain insights into the degree of aggregation and the net helicity. In addition, we apply a theoretical model of supramolecular copolymerization to substantiate the experimental results. We find that the model describes the two-component system well and allows deriving the hetero-interaction energies. The interactions between the same kinds of monomers (BTA-BTA and thioBTA-thioBTA) are slightly more favorable than those between different monomers (BTA-thioBTA), corresponding to a nearly random copolymerization. Finally, to study the interactions of the monomers at the molecular level, we perform density functional theory-based computations. The results corroborate that the two-component system exhibits a random distribution of the two monomer units along the copolymer chain.

How Defects Control the Out-of-Equilibrium Dissipative Evolution of a Supramolecular Tubule

Supramolecular architectures that work out-of-equilibrium or that can change in specific ways when absorbing external energy are ubiquitous in nature. Gaining the ability to create via self-assembly artificial materials possessing such fascinating behaviors would have a major impact in many fields. However, the rational design of similar dynamic structures requires to understand and, even more challenging, to learn how to master the molecular mechanisms governing how the assembled systems evolve far from the equilibrium. Typically, this represents a daunting challenge due to the limited molecular insight that can be obtained by the experiments or by classical modeling approaches. Here we combine coarse-grained molecular models and advanced simulation approaches to study at submolecular (<5 Å) resolution a supramolecular tubule, which breaks and disassembles upon absorption of light energy triggering isomerization of its azobenzene-containing monomers. Our approach allows us to investigate the molecular mechanism of monomer transition in the assembly and to elucidate the kinetic process for the accumulation of the transitions in the system. Despite the stochastic nature of the excitation process, we demonstrate how these tubules preferentially dissipate the absorbed energy locally via the amplification of defects in their supramolecular structure. We find that this constitutes the best kinetic pathway for accumulating monomer transitions in the system, which determines the dynamic evolution out-of-equilibrium and the brittle behavior of the assembly under perturbed conditions. Thanks to the flexibility of our models, we finally come out with a general principle, where defects explain and control the brittle/soft behavior of such light-responsive assemblies.

Insights into the Kinetics of Supramolecular Comonomer Incorporation in Water

Multicomponent supramolecular polymers are a versatile platform to prepare functional architectures, but a few studies have been devoted to investigate their noncovalent synthesis. Here, we study supramolecular copolymerizations by examining the mechanism and time scales associated with the incorporation of new monomers in benzene-1,3,5-tricarboxamide (BTA)-based supramolecular polymers. The BTA molecules in this study all contain three tetra(ethylene glycol) chains at the periphery for water solubility but differ in their alkyl chains that feature either 10, 12 or 13 methylene units. C₁₀BTA does not form ordered supramolecular assemblies, whereas C₁₂BTA and C₁₃BTA both form high aspect ratio supramolecular polymers. First, we illustrate that C₁₀BTA can mix into the supramolecular polymers based on either C₁₂BTA or C₁₃BTA by comparing the temperature response of the equilibrated mixtures to the temperature response of the individual components in water. Subsequently, we mix C₁₀BTA with the polymers and follow the copolymerization over time with UV spectroscopy and hydrogen/deuterium exchange mass spectrometry experiments. Interestingly, the time scales obtained in both experiments reveal significant differences in the rates of copolymerization. Coarse-grained simulations are used to study the incorporation pathway and kinetics of the C₁₀BTA monomers into the different polymers. The results demonstrate that the kinetic stability of the host supramolecular polymer controls the rate at which new monomers can enter the existing supramolecular polymers.

Ring-opening supramolecular polymerization controlled by orthogonal non-covalent interactions

The π–π interaction has been successfully utilized to orthogonally regulate the supramolecular polymerization driven by quadruple hydrogen bonding.

Differentiating the mechanism of self-assembly in supramolecular polymers through computation

The mechanism by which monomers in solution, beyond a certain concentration or below a certain temperature, self-assemble to form one dimensional supramolecular polymers determines much of the bulk properties of the polymer.

Resistive switching in an organic supramolecular semiconducting ferroelectric

The combination of switchable dipolar side groups and the semiconducting core of the newly synthetized C3-symmetric benzotrithiophene molecule (BTTTA) leads to an ordered columnar material showing continuous tunability from injection- to bulk-limited conductivity modulation.

Impact of the water-compatible periphery on the dynamic and structural properties of benzene-1,3,5-tricarboxamide based amphiphiles

The consequences of using saccharides versus tetra(ethyleneglycol) chains as water-compatible moieties on the morphology and dynamics of supramolecular polymers in aqueous solutions are investigated. The saccharides form many H-bonds with other saccharides within the polymer and with water, increasing the hydration of the fiber and changing its dynamics.

Molecular modelling of supramolecular one dimensional polymers

Supramolecular polymers exemplify the need to employ several computational techniques to study processes and phenomena occuring at varied length and time scales. Electronic processes, conformational and configurational excitations of small aggregates of chromophoric molecules, solvent effects under realistic thermodynamic conditions and mesoscale morphologies are some of the challenges which demand hierarchical modelling approaches. This review focusses on one-dimensional supramolecular polymers, the mechanism of self-assembly of monomers in polar and non-polar solvents and properties they exhibit. Directions for future work are as well outlined.