DNA-Functionalized Supramolecular Polymers: Dynamic Multicomponent Assemblies with Emergent Properties.

Analytical ultracentrifugation (AUC) is the leading technique for determining the molar mass, state of association in solution, and association constants of biological macromolecules. Even though it is little used for supramolecular polymers, this technique has already been shown to represent one of the best options in the characterization of these systems. The use of supramolecular assemblies in the field of nanotechnology requires the arrangement of such systems on surfaces, from solution. Therefore, the control and investigation of solution properties is of major importance. In this contribution we highlight the applicability and advantages of using AUC by presenting a summary of the results of the past few years on the characterization of various types of synthetic polymers and supramolecular polymer systems.

Inspired by the dynamic assembly of fibrillar proteins in biology, research on supramolecular polymers has progressed rapidly toward the development of synthetic multicomponent systems. In this review, we highlight recent advances in the study of supramolecular polymers in solution, with an emphasis on how combined computational and experimental approaches deepen our understanding of these systems. In particular, these studies have elucidated the mechanisms of protein aggregation and provided insights into the characteristics of synthetic systems. We discuss the classification of these polymers and systems, highlighting how their different interaction modes and microstructures give rise to diverse structural and functional properties. In addition, we outline the emerging role of machine learning as a powerful tool to navigate the inherent complexity of these systems, thereby enhancing strategies for rational design and characterization. This review highlights how computational approaches, from traditional modeling to emerging machine learning techniques, enable the experimental characterization and understanding of supramolecular polymer chemistry.

Inspired by the dynamic assembly of fibrillar proteins in biology, research on supramolecular polymers has progressed rapidly toward the development of synthetic multicomponent systems. In this review, we highlight recent advances in the study of supramolecular polymers in solution, with an emphasis on how combined computational and experimental approaches deepen our understanding of these systems. In particular, these studies have elucidated the mechanisms of protein aggregation and provided insights into the characteristics of synthetic systems. We discuss the classification of these polymers and systems, highlighting how their different interaction modes and microstructures give rise to diverse structural and functional properties. In addition, we outline the emerging role of machine learning as a powerful tool to navigate the inherent complexity of these systems, thereby enhancing strategies for rational design and characterization. This review highlights how computational approaches, from traditional modeling to emerging machine learning techniques, enable the experimental characterization and understanding of supramolecular polymer chemistry.

ConspectusSince its inception in the early 1990s, the field of supramolecular polymers (SPs) has grown into an interdisciplinary field of chemistry. It expanded from the self-assembly of molecular building blocks based on H-bonding into the realm of complex dynamic material, encompassing both supramolecular noncovalent and molecular covalent regimes. It has paved the path for a more diverse field of research into a new class of polymeric materials, coined dynamic polymers or dynamers. Dynamers are bringing a paradigm shift not only in material science research but also in a broad field of applications from self-healing materials to biocompatible polymeric materials. The present Account presents the evolution of supramolecular polymer chemistry from simple linear polymeric chains to complex dynamic polymers imparting novel functional properties, such as component exchange and self-healing. We explore how SPs led to materials of increasing complexity, starting from simple main-chain polymers to the formation of more complex columnar SPs and lateral SPs. The field has experienced three partially overlapping periods. The main goal was first the generation of polymeric entities from various molecular components connected through noncovalent interactions, especially complementary hydrogen bonding recognition patterns as well as stacked columnar SPs. Thereafter, attention was directed in parallel to the exploration of the properties of SPs and their applications as novel materials. In a third period, the dynamic properties of supramolecular polymers were explored, taking advantage of the lability of noncovalent interactions to perform component rearrangement and exchange. We illustrate how the field of SPs has emerged as a multidisciplinary field of chemistry, biology, and materials science with selected examples from the literature. The SPs, specifically dynamic owing to their inherent reversibility, also pave the path to easier sorting and recycling, as desired in the plastics industry.One of the biggest challenges that the plastics industry is facing today is the end-of-life fate of plastics. Plastics that cannot be recycled end up in landfills or are improperly disposed of in rivers and oceans, polluting and damaging the environmental balance irreversibly. Dynamic polymeric materials presenting inherent dynamicity could pave the way for addressing this long-standing challenge of nonrecyclability of plastics. Dynamers formed via noncovalent interactions or reversible covalent bonds can be broken into components that could be easily recycled and reused. Therefore, dynamers could play a pivotal role toward closing the loop for the plastics industry and provide a solution to an elusive circular economy with plastics being an integral part.

The present work takes an overarching look on how particles can alter the functional and structural properties of shape memory alloys (SMAs). We consider precipitates which form in binary and ternary NiTi-based alloys, including the high-temperature SMAs NiTiHf and NiTiZr. We also take a look at precipitates which form in Cu–Al–Zn, Cu–Al–Ni, and Co–Ni–Ga–SMAs. We take these alloy systems as examples to review different effects of particles on local alloy chemistry and local stress and strain states at particle/matrix interfaces. Their influence on the nucleation and growth of martensite and on the propagation of a martensitic transformation front is discussed, and the consequences for macroscopic functional and structural properties like phase transformation temperatures and widths of thermal hysteresis are highlighted. Emphasis is also placed on particles which form because elements like C and O are picked up during alloy production and affect functional and structural properties. Finally, it is suggested to take a look at additive manufactured SMAs with added inert nano/micro-particles, which would facilitate the investigation of the mechanical constraints, and which may lead to SMAs with improved structural and functional properties.

The use of synthetic supramolecular polymers, built with monomers that self-assemble via non-covalent, reversible interactions, is rapidly growing in many fields, including energy, environmental, and bioengineering applications. Very recently, ureido–pyrimidinone (UPy)-based supramolecular polymers have been used to synthesize biocompatible hydrogels aiming to mimic the dynamic environment of extracellular matrices. Tuning the dynamics, stiffness, and bioactivity of UPy hydrogels effectively influences cellular behaviour and tissue development. However, a complete understanding of UPy-network dynamics over different length and time scales is still lacking, and even the most advanced experimental approaches are unable to capture the dynamics of monomer exchange with atomistic resolution. Here we present a computational study on UPy supramolecular assemblies in water that uncovers the mechanism of monomer exchange between the UPy supramolecular polymers and their surroundings. Our results, based on atomistic molecular dynamics (MD) simulations combined with enhanced sampling and machine-learning (ML) techniques, show that the fine interplay of solute–solvent interactions is the main engine of monomer motion, which makes UPy supramolecular polymer ends more dynamic as compared to the static backbone. This computational work complements the qualitative experimental evidence on supramolecular dynamics with the mechanism of monomer exchange, revealing the most favorable environment for supramolecular polymer damage as well as the underlying principle of self-healing.

Thriving natural systems precisely regulate their complex chemical organizations in space and time by recruitment of a complex network of fuel-driven, kinetically controlled, out-of-equilibrium transformations. Indeed this provides an active, adaptive and autonomous smart actions & functions. In contrast, synthetic systems exhibit simpler behavior owing to thermodynamically driven supramolecular polymerization with no temporal modulation of spatial organization. Stimulated by an outstanding control that nature demonstrates, a drive towards artificial out-of-equilibrium systems with the ambition to program activation and duration of structural transformations has emerged. To realize this vision, overwhelming efforts across the globe have been initiated to design temporally programmed synthetic supramolecular polymers. In an attempt to contribute to this trending field, our supramolecular chemistry group has thoroughly investigated a structure–property relationship that determines the mechanism of supramolecular polymerization. Exploiting these mechanistic insights, along with a bio-inspired fuel-driven enzyme mediated approach, we further attempted to program supramolecular polymers in both structural and temporal regimes. We believe, nature is the inspiration to the current era challenges and it also provides with the solution, a fuel-driven approach to address these. In this account, we shall discuss the efforts made by our group to build generic concept to create temporally programmable supramolecular polymers.

Challenges in the development of organic and hybrid molecular systems

Owing to the mastery exhibited by Nature in integrating both covalent and noncovalent interactions in a highly efficient manner, the quest to construct polymeric systems that rival not only the precision and fidelity but also the structure of natural systems has remained a daunting challenge. Supramolecular chemists have long endeavored to control the interplay between covalent and noncovalent bond formation, so as to examine and fully comprehend how function is predicated on self-assembly. The ability to reliably control polymer self-assembly is essential to generate "smart" materials and has the potential to tailor polymer properties (i.e., viscosity, electronic properties) through fine-tuning the noncovalent interactions that comprise the polymer architecture. In this context, supramolecular polymers have a distinct advantage over fully covalent systems in that they are dynamically modular, since noncovalent recognition motifs can be engineered to either impart a desired functionality within the overall architecture or provide a designed bias for the self-assembly process. In this Account, we describe engineering principles being developed and pursued by our group that exploit the orthogonal nature of noncovalent interactions, such as hydrogen bonding, metal coordination, and Coulombic interactions, to direct the self-assembly of functionalized macromolecules, resulting in the formation of supramolecular polymers. To begin, we describe our efforts to fabricate a modular poly(norbornene)-based scaffold via ring-opening metathesis polymerization (ROMP), wherein pendant molecular recognition elements based upon nucleobase-mimicking elements (e.g., thymine, diaminotriazine) or SCS-Pd(II) pincer were integrated within covalent monofunctional or symmetrically functionalized polymers. The simple polymer backbones exhibited reliable self-assembly with complementary polymers or small molecules. Within these systems, we applied successful protecting group strategies and template polymerizations to enhance the control afforded by ROMP. Main-chain-functionalized alternating block polymers based upon SCS-Pd(II) pincer-pyridine motifs were achieved through the combined exploitation of bimetallic initiators and supramolecularly functionalized terminators. Our initial design principles led to the successful fabrication of both main-chain- and side-chain-functionalized poly(norbornenes) via ROMP. Utilizing all of these techniques in concert led to engineering orthogonality while achieving complexity through the installation of multiple supramolecular motifs within the side chain, main chain, or both in our polymer systems. The exploitation and modification of design principles based upon functional ROMP initiators and terminators has resulted in the first synthesis of main-chain heterotelechelic polymers that self-assemble into A/B/C supramolecular triblock polymers composed of orthogonal cyanuric acid-Hamilton wedge and SCS-Pd(II) pincer-pyridine motifs. Furthermore, supramolecular A/B/A triblock copolymers were realized through the amalgamation of functionalized monomers, ROMP initiators, and terminators. To date, this ROMP-fabricated system represents the only known method to afford polymer main chains and side chains studded with orthogonal motifs. We end by discussing the impetus to attain functional materials via orthogonal self-assembly. Collectively, our studies suggest that combining covalent and noncovalent bonds in a well-defined and precise manner is an essential design element to achieve complex architectures. The results discussed in this Account illustrate the finesse associated with engineering orthogonal interactions within supramolecular systems and are considered essential steps toward developing complex biomimetic materials with high precision and fidelity.

Starch is the main integral components of the millets and it is widely used in the food processing sectors for development of functional foods. The extraction and isolation methods of starch from millet grains are greatly affected their functional and structural properties. Therefore, in current study, the effects of different wet milling extraction methods such as water, acidic, and alkaline are investigated on the physical, structural, thermal, and functional properties of barnyard millet starch. The results show that the starch extracted from barnyard millets using alkaline method shows higher yield of starch (64.76%) with good amylose content (34.52%). In addition, the functional properties such as water binding capacity (211.39%), oil binding capacity (223.84%), higher color attributes (whiteness), thermal stability (91.62 °C), textural properties (74.70 g), and lower particle size (19.44 µm) are recorded in barnyard millet starch extracted using alkaline steeping method. The results of the field emission scanning electron microscopes (FESEM) are showed polygonal, spherical, and rounded shapes of all types of extracted starch granules. Whereas, the acidic method is more fused structures of starch granules as compared to water and alkaline methods. The results of the current study reveal that the application of alkaline method is the most potential to extract starch from barnyard millet with good quality and functional properties for further food applications.

A series of poly(lactide) (PLA)‐based supramolecular polymers based on linear PLLA‐b‐PCL‐b‐PLLA triblock copolymers (PLLA, poly(l‐lactide); PCL, poly(ε‐caprolactone)) or/and three‐arm star (PCL‐b‐PDLA)3 block copolymers (PDLA, poly(d‐lactide)) were synthesized. The effects of the structure and composition on crystal structure, crystallization behavior, spherulite morphology and mechanical properties of the synthesized supramolecular polymers were investigated. The results of DSC and polarized optical microscopy indicated that the supramolecular polymer exhibited poor crystallization ability with respect to PCL/PLA block copolymer, and the crystallinity of the supramolecular polymer with alternating PCL/PLA multiblock structure was stronger than that with similar crosslinked network structure. The presence of molten PCL blocks disturbed the orientation of lamellae, forming spherulites with feather‐like dendrites, and ring‐banded spherulites were observed as the molecular weight of the PLA blocks increased. The results of tensile tests demonstrated that supramolecular polymers with larger molecular weight of PLA blocks showed the pronounced ductile fracture. On this basis, stereocomplexed supramolecular polymers were also synthesized, and it was found that the stereocomplex crystals had a significant impact on the crystallization and mechanical properties of the supramolecular polymers. Therefore, in this work a novel technique for manufacturing toughened PLA‐based material and tuning its performances is proposed, which may promote the application of PLA‐based materials in more fields. © 2022 Society of Industrial Chemistry.

Engineered nanomaterials and hybrid molecular systems have emerged as transformative platforms uniting advanced therapeutics with sustainable energy storage technologies. In biomedical applications, functional nanostructures—ranging from polymer–inorganic hybrids to bioinspired core–shell architectures—enable targeted drug delivery, tunable release kinetics, improved biocompatibility, and real-time bioimaging. Hybrid molecular systems such as lipid–polymer conjugates, peptide-functionalized metal–organic frameworks, and graphene–biopolymer composites achieve multifunctionality critical for navigating complex pathological microenvironments. Recent therapeutic breakthroughs report particle size control within 50–150 nm for optimal tumor accumulation, and drug encapsulation efficiencies exceeding 90%, enabling precise and efficient treatment modalities. In sustainable energy storage, nanostructured hybrids incorporating conductive polymers, carbon allotropes, and transition metal compounds demonstrate high specific capacitance (>400 F g⁻¹), rapid charge–discharge rates, and extended cycle stability (>10,000 cycles). Dual-function nanoplatforms now integrate photothermal therapy with photovoltaic energy harvesting, while bio-derived hybrids offer concurrent therapeutic delivery and supercapacitor performance. Notably, bio-inspired design principles enable cost-effective synthesis and resource-efficient scalability, aligning with circular economy goals. This review critically examines design strategies, synthesis methodologies, and performance metrics governing these multifunctional materials, with emphasis on their cross-domain adaptability. The synergistic integration of therapeutic and energy storage functionalities is anticipated to catalyze a new class of high-performance, resource-conscious technologies, bridging healthcare innovation and sustainable energy solutions.

Topological features of one-dimensional macromolecular chains govern the properties and functionality of natural and synthetic polymers. To address this issue in supramolecular polymers, we synthesized two topologically distinct supramolecular polymers with intrinsic curvature, circular and helically folded nanofibers, from azobenzene-functionalized supramolecular rosettes. When a mixture of circular and helically folded nanofibers was exposed to UV light, selective unfolding of the latter open-ended supramolecular polymers was observed as a result of the curvature-impairing internal force produced by the trans-to-cis photoisomerization of the azobenzene. This distinct sensitivity suggests that the topological features of supramolecular polymers define their mechanical stability. Furthermore, the exposure of circular supramolecular polymers in more polar media to UV irradiation resulted in ring opening followed by chain elongation, thus demonstrating that the circular supramolecular polymer can function as a topological kinetic trap.

While the sensitive dependence of the functional characteristics of self-assembled nanofibers on the molecular structure of their building blocks is well-known, the crucial influence of the dynamics of the assembly process is often overlooked. For natural protein-based fibrils, various aggregation mechanisms have been demonstrated, from simple primary nucleation to secondary nucleation and off-pathway aggregation. Similar pathway complexity has recently been described in synthetic supramolecular polymers and has been shown to be intimately linked to their morphology. We outline a general method to investigate the consequences of the presence of multiple assembly pathways, and show how kinetic analysis can be used to distinguish different assembly mechanisms. We illustrate our combined experimental and theoretical approach by studying the aggregation of chiral bipyridine-extended 1,3,5-benzenetricarboxamides (BiPy-1) in n-butanol as a model system. Our workflow consists of nonlinear least-squares analysis of steady-state spectroscopic measurements, which cannot provide conclusive mechanistic information but yields the equilibrium constants of the self-assembly process as constraints for subsequent kinetic analysis. Furthermore, kinetic nucleation-elongation models based on one and two competing pathways are used to interpret time-dependent spectroscopic measurements acquired using stop-flow and temperature-jump methods. Thus, we reveal that the sharp transition observed in the aggregation process of BiPy-1 cannot be explained by a single cooperative pathway, but can be described by a competitive two-pathway mechanism. This work provides a general tool for analyzing supramolecular polymerizations and establishing energetic landscapes, leading to mechanistic insights that at first sight may seem unexpected and counterintuitive.

A novel approach for the facile synthesis of zinc oxide/carbon hybrid systems from corn distillers soluble: Surface modification and characterization for sustainable remediation