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Aug 2026

Fluctuation Effects on the Order–Disorder Transition of Symmetric Block Copolymers Mixed with Random Copolymers or Homopolymers

Blending block copolymers (BCPs) with polymeric additives provides a direct route to controlling microphase separation, yet how such additives alter composition fluctuations remains incompletely understood. Here, we examine the order–disorder transition (ODT) in symmetric AB diblock copolymers mixed with either neutral random copolymers (RCPs) or symmetric pairs of A and B homopolymers (HPs). Fluctuation effects are quantified using Langevin field-theoretic simulations combined with well-tempered metadynamics and compared with fluctuation-free self-consistent field theory calculations. In BCP–RCP mixtures, RCP addition shifts the transition toward stronger incompatibility and amplifies the fluctuation-induced correction as the additive concentration increases. In mixtures containing A and B HPs, the response differs qualitatively, and the HP chain length controls both the direction of the transition shift and the magnitude of the fluctuation correction. Short HPs enhance the destabilization of lamellar order by fluctuations, whereas longer HPs suppress this effect. When fluctuations are included, the crossover in the overall ODT response shifts somewhat below its mean-field value. Together, these results show that polymeric additives alter the ODT through coupled mean-field and fluctuation effects, so their impact cannot be inferred from mean-field phase behavior alone.

Wonjun Kang, Hyeon U Jeong, Daeseong Yong et al. · 0 citations
Aug 2026

The effect of incorporation of different hydrophobic pluronics on the evolution of liquid crystalline structures in a nonionic microemulsion.

This research article describes water-driven phase changes in a microemulsion composed of TPGS-Capryol 90 as a surfactant mixture and clove oil as an oil phase. After optimizing the surfactant mixture, Pluronics® of different hydrophobicity (L121, P123, and P105) were incorporated into Smix at a fixed concentration for delineating their effects on the formation of liquid crystalline (LC) structures. Characterization studies were performed along a water dilution line constructed within the monophasic region. The data were obtained using polarised light microscopy (PLM), small-angle X-ray scattering (SAXS) and rheology experiments. We recorded a progressive transformation of the microemulsion into lamellar LC structures upon increasing the water content from 20 to 40%. SAXS data showed well-defined peaks corresponding to lamellar ordering. The effect of Pluronics® could be noticed in the inter-lamellar spacing, which followed the order: P123 > P105 > L121. While comparing the data obtained at an identical water level, we found that hydrophobic L121 favoured the formation of tightly packed and weakly hydrated lamellae. Relatively hydrophilic Pluronics® (P123 and P105) produced swollen ones. This interpretation was further supported by rheological analyses, which showed that LC structures carrying L121 could resist shear to a higher degree. In contrast, structures formed with P123 and P105 appeared to be deformable. Collectively, these results underscore the potential utility of triblock copolymers for tuning the mechanical and viscoelastic properties of mesophasic structures.

Nutan Kishanrao Chavan, K. Kaushik, Karan Bisht et al. · 0 citations
Open access Aug 2026

Conformational Behavior and Self-Assembly of Gallol-Containing Block Copolymers in Non-Polar Media

While previous studies have illuminated the behavior of poly(gallol methacrylate)-block-poly(N-phenylmethacrylamide) copolymers (PM-b-PNP) in polar alcoholic mixtures, their performance in non-polar environments remains an uncharted territory. In this study, full-atomistic molecular dynamics (MD) simulations were first employed to investigate the conformational behavior and aggregation of experimentally relevant homo- and block copolymer architectures in heptane. The theoretical findings were subsequently supported through experimental studies using polymers synthesized via controlled reversible addition fragmentation chain transfer (RAFT) polymerization. Our results highlight the critical role of intramolecular hydrogen bonding in stabilizing specific conformations and helix-like structures of PNP homopolymers and the leading role of attractive van der Waals interactions in the aggregation of block copolymers.

N. K. Balabaev, Puja Poddar, Subhadeep Shit et al. · 0 citations
Review Aug 2026

Polymorphic Crystalline Structure and Properties of Polyamides

The polymorphic supermolecular structure of semicrystalline polymers exerts a decisive influence on their macroscopic properties, which is particularly pronounced in polyamide systems dominated by hydrogen bonding. This paper collates the formation mechanisms, regulation strategies and structure‐property relationships between polymorphic structures and macroscopic properties of polyamide systems reported in recent years. The regulation methods for the polymorphic crystalline structure of polyamides, based on polymorphism and Brill transition behavior, are categorized into three types: chemical methods involving random copolymerization and block copolymerization; physical methods including polymer blending, nucleating agent incorporation and solution induction; and processing methods such as stretching, shear fields, temperature fields and their coupled fields. The comprehensive properties of polyamides, especially mechanical, thermal, barrier and optical properties, can be effectively tailored via the regulation of their crystalline structures. By systematically reviewing the existing research progress, this review aims to deepen the understanding of the evolution mechanism of polyamide polymorphism and provide novel insights for the development of high‐performance polyamide materials.

Zhihao Lin, Weihong Zeng, Yunqi Xu et al. · 0 citations
Open access Aug 2026

Effects of Structural Ordering on the Thermal Diffusivity of Liquid-Crystalline Poly(ester imide) Nanofibers

The development of polymer materials with high intrinsic thermal conductivity is essential for efficient heat dissipation in next-generation electronics. In this study, we report the fabrication and characterization of liquid-crystalline (LC) polyimide nanofibers (PI-NFs) designed to achieve a highly ordered internal structure. Highly aligned LC-PI-NFs were prepared via electrospinning of a poly(amic acid) precursor containing rigid phenyl benzoate mesogens and flexible dodecyl spacers, followed by stepwise thermal imidization. To further enhance molecular alignment, uniaxial tensile drawing was applied during the imidization process. Upon thermal imidization, wide-angle X-ray scattering (WAXS) revealed a phase transition from the initial smectic (Sm) A phase to a more ordered SmF phase. Furthermore, combined WAXS and small-angle X-ray scattering (SAXS) analyses suggested that uniaxial drawing enhances the ordering of the LC structure. Microscale temperature wave analysis demonstrated a positive correlation between the internal structural order and the thermal diffusivity along the fiber axis, which reached a value of 6.6 × 10–7 m2 s–1 (corresponding to a thermal conductivity of 1.0 W m–1 K–1) for the uniaxially drawn LC-PI-NFs. These results demonstrate that synergistically integrating LC phase behavior with processing-induced strain is a promising strategy for developing high-performance, thermally conductive polymer nanostructures.

Ryuji Murai, Hayato Maeda, Yuqian Chen et al. · 0 citations
Open access Aug 2026

Interplay of crosslinking architecture and interparticle interactions in microgel suspension rheology.

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 · 0 citations