Amphiphilic polymer co‐networks (APCNs) offer a versatile platform as materials for numerous applications, yet their rational design requires a fundamental understanding of the complex interplay between molecular architecture and macroscopic properties. Here, we present a well‐defined model platform based on the heterocomplementary coupling of tetra‐PEG and tetra‐PCL star polymers. This system enables the systematic exploration of how synthesis conditions govern network formation, mechanical response, and transport behavior. Network properties were characterized through swelling studies and rheology, while the diffusion of star polymers was probed using combined Fluorescence Recovery After Photobleaching (FRAP) and Forced Rayleigh Scattering (FRS). Complementary Dynamic Light Scattering (DLS) experiments with diffusive probes enabled the extraction of diffusion‐governing length scales, such as the network correlation length and the hydrodynamic screening length. This multi‐methodological approach establishes quantitative structure–property–transport relationships and highlights the interplay between synthesis, network architecture, and functional properties. The PEG–PCL model APCN platform thus provides a predictive framework for the rational design of tailor‐made amphiphilic materials with tunable mechanics and transport characteristics.
HYPOTHESIS
Poly(N-isopropylacrylamide) (PNIPAM) microgels are highly porous polymer networks whose mechanical properties are governed not only by environmental factors but also by their internal architecture. We hypothesize that the internal structure of microgels, together with interparticle interactions, synergistically regulates the macroscopic rheological behavior of microgel suspensions.
EXPERIMENTS
Frequency-sweep measurements were performed to identify the suspension states, evaluate shear-induced structural breakdown and recovery, and monitor continuous volume phase transitions under different conditions. The correlation between the loss tangent (tan(δ)) and the low-frequency power-law viscoelastic exponents were further analyzed. Critical transition points extracted from temperature sweeps were used to construct phase diagrams, describing phase distributions and transition pathways governed by temperature, concentration, and salt.
FINDINGS
Crosslinking architecture markedly altered the thermal response pathway of PNIPAM microgel suspensions and determined their ability to recover after shear-induced structural breakdown. Salt addition reshaped phase-transition pathways by screening electrostatic repulsion, while simultaneously amplifying architecture-dependent rheological differences among suspensions. These findings confirm that microgel suspension rheology is governed by the coupling between internal crosslinking architecture and interparticle interactions.
Li Zhang, Wei Liu, To Ngai· Journal of Colloid and Inter...· 0 citations
The solution‐state aggregation of conjugated polymers critically determines the morphology and performance of organic solar cells (OSCs), yet processing optimization remains largely empirical. Here, we establish the sol–gel transition temperature (
T
sol–gel
), determined by rheology, as a transferable descriptor linking solution aggregation to film formation and device performance. Using cryo‐electron microscopy (CEM), small‐angle neutron scattering (SANS), and rheology, we reveal that the high‐performance donor polymer D18 in chlorobenzene evolves from dissolved wormlike chains to a weak gel and then to a strong gel upon cooling. Importantly, processing near the
T
sol–gel
temperature yields weak‐gel aggregates, which transform into a double fibril network during film formation, enabling enhanced charge transport, optimized phase separation, and uniform large‐area coating. Under this condition, D18:L8‐BO achieves a power conversion efficiency of 19.6% in small‐area devices and 17.1% in 17.6 cm
2
mini‐modules. More importantly, this
T
sol–gel
‐guided strategy is further validated in multiple conjugated polymers in OSCs, including PM6, PffBT4T‐2OD, and D18 processed from
o
‐xylene, where the optimal performance consistently occurs near the corresponding sol–gel transition. These results identify weak‐gel pre‐aggregation near
T
sol–gel
as a general processing window for constructing favorable fibrillar morphologies and provide a broadly applicable framework for morphology control in high‐performance OSCs.
ABSTRACT 2D covalent organic frameworks (COFs) have emerged as promising functional materials for catalysis, adsorption, sensing, and energy storage. Their interfacial behavior and surface microenvironment play a decisive role in performance, yet these features are typically considered static or irreversible due to the lack of dynamic structure models. In this study, we report the construction of an ionic COF (iCOF), I‐4, designed through precise tuning of its skeleton and counterions, which uniquely exhibits reversable dynamic exfoliation and aggregation behavior in aqueous environments. This enables bidirectional control over particle size and phase states. Photocatalytic hydrogen evolution (PHE) studies reveal a strong correlation between solution concentration, particle size, and hydrogen production efficiency. Notably, I‐4 achieves a remarkable PHE rate of 190 mmol g−1 h−1 at 35°C. Moreover, the material can be fully precipitated and recovered from solution by simple iodide salt addition, enabling closed‐loop material recycling. Mechanistic analysis based on weak‐force interactions and soft‐hard acid‐base theory provides insight into the dynamic exfoliation process, highlighting the synergistic roles of counterion assembly and framework structure. These findings pave the way for the tailored synthesis of next‐generation dynamic COF materials with reversible interfacial adaptability, offering broad application potential in catalysis, ion transport, and molecular separation.
Jilu Yang, Xiaofei Zhang, Yue Li et al.· Advancement of science· 0 citations
An integrated analysis of gelation kinetics, micellization thermodynamics, and viscoelastic properties (G′, G″) of Pluronic F127-based hydrogels is provided to support the rational design of thermoresponsive hydrogels and identify critical knowledge gaps to guide future research in advanced therapeutic biomaterials.
Sharifah Nafisah Syed Ismail, H. Holilah, Lisman Suryanegara et al.· Polymer Bulletin· 0 citations
Developing high-performance impact-stiffening polymers that are broadly applicable across chemical systems remains a key challenge, as existing designs rely on meticulously engineered molecular motifs. Inspired by water’s role in biological impact resistance, we introduce a generalizable biomimetic paradigm. We transform water—commonly considered a property-limiting plasticizer—into an active, rate-sensitive cross-linker by structurally confining bound-water networks within proton-rich polymer scaffolds. Programming their dissociation kinetics enables a sharp, reversible soft-to-rigid transition under impact via kinetic freezing. This design, demonstrated in a poly(thioctic acid)-based system, concurrently achieves outstanding energy dissipation, self-healing, and strong adhesion. Crucially, it bypasses de novo synthesis of specialized motifs and is applicable across diverse polymer backbones, establishing programmable water dynamics as a versatile principle for adaptive polymeric materials. Impact stiffening polymers typically rely on specific chemical structures to enable dynamic cross-linking. Here, the authors report an impact-stiffening system which utilises the crosslinking of residual water to form dynamic hydrogen bonds within poly(thioctic acid) networks, which is appliable to variety of polymer networks.
Siyu Jin, Zhaoming Zhang, Menghao Ji et al.· Nature Communications· 0 citations
Converting polyethylene (PE) into dynamic covalent networks represents a crucial pathway toward achieving sustainability in polyolefins. In this study, PE‐Vitrimers with gradient cross‐link densities were constructed, and their non‐isothermal crystallization behavior was systematically investigated using multiple kinetic models. It was found that the influence of the dynamic cross‐linked network on non‐isothermal crystallization is primarily manifested as a reshaping of the kinetic evolution pathway rather than thermodynamic disruption of the crystal structure. Although the introduction of the cross‐linked network does not alter the inherent orthorhombic crystal system of the PE matrix, the polar cross‐linking nodes enhance the Avrami exponent via heterogeneous nucleation effects and induce anisotropic crystal growth. Meanwhile, the steric hindrance arising from the dense topological network gradually dominates, leading to a monotonic decrease in the overall crystallization rate, accompanied by a global upward shift and a non‐monotonic decrease‐then‐increase evolution of the local crystallization activation energy with conversion. This work elucidates the physical competition mechanism between cross‐link‐induced heterogeneous nucleation and topological constraints, providing important theoretical support for the processing design of semi‐crystalline Vitrimer.
Kai Niu, Chenchao Fu, Xudong Xu et al.· Polymer Engineering & Sc...· 0 citations