Nano- and micromotors are a class of active colloids that can self-propel outperforming Brownian motion. Polymer synthesis or degradation are alternative ways to enzyme-based or externally-driven strategies to induce self-propulsion in particles, but they are often limited due to the reaction conditions. Nature leverages biopolymerization reactions to sustain locomotion either of whole microorganisms or of organelles inside cells. With the aim of integrating natural locomotion strategies into engineered motors, we have begun to explore the propulsion mechanism of the food-borne pathogen Listeria monocytogenes, which expresses the actin-recruiting protein ActA on its surface to harness host cell actin polymerization for rapid intracellular movement. Here, we compare the locomotion of silica particles depending on the ActA immobilization strategy on the motor surface, using either homogeneous coatings, Janus-type coatings, or ActA immobilization within polymer brushes. An up to 5-fold increase in the propulsion of the motors compared to their Brownian motion is observed when Janus motors are considered. The motors orbit around or dock onto larger tracer particles depending on the environmental pH and on whether they are individuals or in clusters. Altogether, these motors illustrate how integration of concepts of the natural and synthetic world can yield unique engineered units.

Size-exclusion chromatography (SEC) equipped with refractive index (RI) and multi-angle light scattering (MALS) detectors was carried out on a polystyrene (PS) sample with the weight-average molecular weight 2.07 ×€104 along with the matrix-assisted laser desorption flight time mass spectrometry (MALDI-TOF-MS). The MALDI-TO-MS result was corrected by the relative sensitivity, which was found to decay exponentially with the molecular weight. Exchanging the elution volume for molecular weight by the calibration relation, the molecular-weight distribution (MWD) curves were obtained from the chromatograms. The MWD curve determined by the SEC chromatogram was much broader than that obtained by MALS and MALDI-TOF-MS because of the peak-broadening effect. Based on the MWD determined by MALDI-TOF-MS, the RI chromatogram was closely described by the calculated values using the Gaussian function. Based on the results of the PS sample, RI and MALS data of polyethylene oxide samples in water were analyzed using the exponentially modified Gaussian equation.

Over the last few years, 4D printing of liquid crystal elastomers (LCEs) has been explored to develop actuators with significant, reversible, and anisotropic shape changes upon external stimuli such as heat or light. Most reported ink formulations rely on photo-curable liquid crystal materials derived from high molecular weight (MW) main-chain macromers. Their rheological properties allow to program molecular alignment during direct ink writing. In contrast, formulations composed mainly of monoacrylate or diacrylate low MW mesogens are unsuitable for extrusion-based 4D printing as they fail to promote mesogen alignment during printing. This shortcoming restricts the range of chemical and physical compositions accessible to 4D printing. Here, we introduce a practical route for formulating 4D printable inks that integrate low MW mesogens. By adding an acrylate-ended macromer to the low MW constituents, these mixtures become suitable for direct ink writing. This enables the preparation of multi-functional actuators with digitally controlled director morphology and tailored properties, for example, stiffness and actuation strain, as well as light-responsive behavior when photoactive molecules are used. These results highlight the versatility of the method and suggest its potential compatibility with other functional low MW units, such as those responsive to electrical or pH stimuli.

The introduction of cleavable bonds into a fully hydrocarbon polymer backbone represents a promising strategy for imparting stimuli-responsive degradability. Here, we demonstrate this concept through the synthesis of degradable cyclic polymers via ring-expansion metathesis copolymerization (REMP) between cyclic enol ether 2,3-dihydrofuran (DHF) and a series of diester- and dicarboximide-functionalized exo-(oxa)norbornene derivatives. The copolymerization behavior is governed by the reactivity of the comonomers and the use of the sterically hindered, tethered ruthenium initiator CB6. NMR analysis confirms a high degree of alternation in the resulting copolymers. Importantly, these materials undergo degradation under mild acidic conditions through hydrolysis of the enol ether moieties embedded within the backbone. This work introduces a versatile platform for the design of degradable cyclic polymers, offering promising prospects for sustainable and responsive polymer materials.

Transient electronics aim to align device lifetime with functional demand by enabling systems that physically dissolve or degrade after completing predefined tasks, thereby mitigating electronic waste and eliminating secondary surgical removal of temporary implants. Achieving this vision requires materials that couple electrical reliability and mechanical resilience with precisely programmable disappearance. Dynamic polymers, constructed from reversible dynamic interactions, provide a unifying strategy to meet these demands. By embedding bond reversibility at the molecular level, these networks enable continuous structural reconfiguration during operation, autonomous self-healing, and stimulus-triggered disassembly, transforming degradation from a passive consequence into an actively tunable function. This review outlines the fundamental chemistries of supramolecular and dynamic covalent polymer systems and analyzes how bond-exchange kinetics govern electromechanical stability, interfacial integrity, and lifetime control in transient devices. We further discuss emerging applications in bioelectronic interfaces, flexible sensors, and energy storage platforms, highlighting the integration of adaptive mechanics with controlled degradation. Finally, we discuss key challenges, including biocompatibility, predictive lifetime programming, heterogeneous device integration, scalable manufacturing, and environmental closure. By positioning reversible chemistry as a central materials doctrine, dynamic polymers redefine transient electronics as adaptive systems capable of stable operation and programmed disappearance within a single molecular framework.

Carbon fiber-reinforced composites (CFRCs) that are based on thermosetting epoxy resins are widely used. However, they are difficult to recycle, thereby posing environmental challenges. Although incorporating reversible dynamic bonds into epoxy networks enables the recycling of CFRCs, achieving strong mechanical properties, reprocessability, and efficient degradation ability under mild conditions remains challenging. In this study, robust epoxy networks were developed using dynamic acylhydrazone bonds to recycle CFRCs. A novel acylhydrazone-containing diamine curing agent was synthesized and used to cure epoxy resin, resulting in an epoxy with excellent chemical and solvent resistance. Synergistic hydrogen bonding and C═N exchange enabled a tensile strength of up to 106.9MPa, retaining > 75MPa after three reprocessing cycles. Under mildly acidic conditions, C═N cleavage enabled the efficient recovery of intact carbon fibers comparable to that of virgin fibers, and the degraded matrix could be reused as an adhesive. This study presents a sustainable approach that combines high strength, reprocessability, degradability, and recyclability in high-performance epoxy networks and CFRCs systems.

Understanding the molecular origin of thermo-optical transitions in ionic-liquid ionogels is essential for rationally designing robust, nonvolatile thermoresponsive devices. Here, a UCST-type poly(hydroxypropyl acrylate) (PHPA)-[EMIM][TFSI] ionogel was constructed via a one-step UV-induced photopolymerization and displayed reversible switching between opaque and transparent states upon heating. By integrating variable-temperature Fourier transform infrared spectroscopy (VT-FTIR) with 2D correlation infrared spectroscopy (2D-COS IR), the transition was traced to a temperature-driven redistribution of noncovalent interactions within the polymer/ionic-liquid matrix. At low temperature, cooperative hydroxyl-centered association dominated the microstructure, while heating progressively weakened polymer-associated hydrogen-bond motifs and promoted polymer-ionic-liquid association involving both hydroxyl and carbonyl environments. This interaction rebalancing diminished microheterogeneity and reduced light scattering, thereby generating the UCST-type opaque-to-transparent transition. The ionogel maintained stable optical switching over repeated thermal cycles and exhibited high sensitivity near the transition region, highlighting its promise for high-resolution temperature sensing and adaptive optical modulation in nonvolatile soft materials.

A linear-dendritic polymer has been explored as a drug delivery vehicle for cancer therapy. In this study, we successfully prepared a tumor microenvironment-responsive, dendronized and block poly[N-(2-hydroxypropyl) methacrylamide] (polyHPMA)-based copolymer-doxorubicin conjugate (pHPMA-block-pDendron-DOX) via two-step reversible addition-fragmentation chain transfer (RAFT) polymerization. The conjugate self-assembled into nanoparticles (NPs). Due to the presence of the Gly-Phe-Leu-Gly (GFLG) tetrapeptide and the hydrazone bond in the structure of the conjugate, cathepsin B-responsive degradation and pH-responsive drug release were realized within the tumor microenvironment. The NPs displayed a distinctive cytotoxic effect on 4T1 cells after internalization through endocytosis pathways. Significant improvements in the accumulation of doxorubicin (DOX) from the NPs were observed at the tumor site in a 4T1 murine breast cancer xenograft model, leading to promising anti-cancer effects. In addition, the side effects of DOX were significantly diminished in the NPs at a high dose. The prepared linear-dendritic conjugate could be used as an efficient and safe nanomedicine.

Cholesteric liquid crystals (CLCs) can be encapsulated within liquid crystal microcapsules (CLCMs) via ultrasonic emulsification, and this microcapsule structure offers advantages in liquid crystal (LC) orientation control and stability. However, CLCMs still face challenges in multiple stimulus responsiveness. In this study, polymerizable LC monomers are introduced as the core filler of CLCMs and polymerized under UV irradiation to form polymer networks. As a result, the structural color of the film changes, and the patterned coloration of the final prepared film gradually disappears upon exposure to sunlight. Furthermore, with the temperature increasing, the pattern of the film first appears and then disappears, ultimately rendering the film completely transparent. Overall, the results show that the CLCM films incorporating polymerizable LC core exhibit multi-stimuli responsiveness to light, heat, and humidity, demonstrating the potential of polymerizable CLCMs for advanced applications such as anti-counterfeiting technologies and sensors.

Micellar drug delivery systems have emerged as a versatile platform for improving the solubility, stability, and targeted release of chemo(immuno)therapeutics. This review focuses on micellar formulations that combine two key design principles: the inherent biodegradability of aliphatic poly(carbonate)s and the universal acid-responsive trigger mechanism. These systems are particularly attractive for tumor therapy, where the acidic microenvironment can be exploited for controlled drug release. We differentiate between two major classes: (i) systems employing acid-labile linkages for reversible conjugation of pharmaceutically active compounds, and (ii) systems in which micelle disassembly or polymer backbone degradation is governed by acid-responsive functionalities. Both categories are systematically evaluated according to the chemical motifs enabling acid sensitivity, including oximes, imines, hydrazones, boronate ester, acetals, ketals, and tertiary amines, among others. The review highlights recent advances in synthetic strategies, structure-property relationships, and therapeutic performance, emphasizing how these design elements synergistically enhance drug loading, release kinetics, and biocompatibility. Finally, we discuss current challenges and future directions for translating these smart micellar systems into promising tumor-targeted (immuno-)therapeutics.