Macromolecular Rapid Communications最新文献

Circularity in plastic waste management through depolymerization to monomer is a promising route to address inefficiencies in the current recycling ecosystem, especially for poly(ethylene terephthalate) (PET). Hydrolysis provides a green solvent to promote the depolymerization of PET, but lifecycle analyses have driven extensive efforts to lower the reaction temperature to minimize greenhouse gas emissions. However, recent work (Nat. Commun., 2025, 16, 3051) has indicated that hydrolysis at temperatures near the normal boiling point of water can generate nanoplastics. Here, we demonstrate that PET hydrolysis at temperatures less than 180°C leads to nanoplastics as determined from dynamic light scattering (DLS) and differential scanning calorimetry (DSC). Clear evidence of plastic nanoparticles is observed after hydrolysis at 150°C for three of the four PET sources examined. DSC thermograms of hydrolysis products on heating exhibit a broad peak with a depressed melting point that is consistent with small PET crystals. Hydrolysis at higher temperatures leads to smaller particles with DSC thermograms that are indicative of small molecules and oligomers. These results illustrate the potential for unintended consequences from efforts to reduce GHG emissions with chemical recycling to generate nanoplastics in the product stream that may be difficult to readily differentiate from expected products.

In photoinduced cationic ring-opening polymerization (ROP) of epoxy monomers, chain-transfer reactions in the presence of alcohols are well established, and monosulfides are known to inhibit polymerization even at very low loadings (i.e., 0.01 mol%). Herein, it is thoroughly investigated the role of a disulfide-containing diol in quenching the polymerization of a difunctional epoxy formulation. Differently from the monosulfide, the propagation can start, and only at high sulfur:epoxy ratio the reactions of the disulfides with the oxonium ions effectively compete with the propagation and stops the polymerization. This inhibition mechanism can be exploited as a novel maskless photolithographic approach, enabling the spatially controlled patterning of epoxy coatings through localized deposition of the disulfide diol. As a proof of concept, sharply defined features with sizes down to 200 µm are successfully fabricated. These results introduce disulfide-mediated polymerization quenching as a versatile and material-efficient method for epoxy photopatterning.

Pyrazine dicarbonitriles functionalized with allyl groups (APQ and BAPPQ) were synthesized to address the high melting point and low curing reactivity of conventional phthalonitrile (PN) resins. APQ exhibits significantly reduced melting temperatures (as low as 50.9 °C) and curing initiation temperatures (around 150°C), along with wide processing windows (up to 150°C). Remarkably, an "Ene" reaction between cyano and allyl groups was identified, leading to imine formation in the early stage of curing below 200°C. Meanwhile, the traditional cyano polymerization mechanism also operates under elevated curing temperature, generating azaisoindoline, azaphthalocyanine, and triazine structures. The resin cured at 275°C shows high thermal stability (T_g = 346.8°C, char yield = 75.8%), and superior flame-retardance performance (HRC = 18.1 J g^-1 K^-1, THR = 1.6 kJ g^-1). This work offers a new strategy for designing processable and high-performance aromatic nitrile resins.

Over the last two decades, there has been substantial development in the manufacturing of nano- and micro- tubes and wires as building blocks for electronic devices, such as field-effect transistors, to complement the conventional semiconductor transistors in electronic circuits. Previous attempts to improve device performance through the development of new materials have focused mostly on carbon or metal oxide-based semiconducting materials. Here, we report a flexible conducting polymer micro-wire grown from the vapor phase via an oxidative polymerization route. Electrical measurements show that the single micro-wires have relatively high conductivity and non-linear electrical characteristics. In addition, we demonstrate the fabrication of a flexible polythiophene micro-wire organic electrochemical transistor, in which the channel and gate are made of single micro-wires. These devices are fully compatible with conventional fabrication processes and operate in the sub-volt regime, and have the potential to be scaled to larger multi-micro-wire architectures and circuits. This study demonstrates the concept of self-assembly of organic molecules and simultaneous polymerization to generate complex, ordered, and functional structures resembling polymerized Bechgaard salts.

The semi-aromatic co-polyamide PA6T/66, known for its high thermal stability, low moisture absorption, and promising melt-processability, is generally regarded as a typical eutectic copolymer. However, there is no adequate understanding of the eutectic behavior under the coupled field of temperature and pressure that widely exists in melt processing. In this work, a series of PA6T/66 samples crystallized under coupled temperature-pressure fields were investigated using a combination of differential scanning calorimetry and in situ wide/small angle X-ray scattering. Unexpected multi-stage melting indicated comonomer partition across cocrystal domains, providing evidence of pseudo-eutectic behavior. Under coupled temperature-pressure fields, segments with long 6T sequences aggregated and formed cocrystals at a higher temperature, while the excluded segments with shorter 6T sequences subsequently formed cocrystals at a lower temperature. This led to the generation of cocrystals with different compositions of 6T repeat units. This work clarifies the structure evolution of PA6T/66 under coupled temperature-pressure fields and provides an efficient strategy for the performance improvement of semi-aromatic polyamide copolymer products.

Modulating biomaterial properties using light holds great promise for biomedical applications, such as drug delivery, as it is non-invasive and offers both spatial and temporal control. Visible light is particularly salient for stimulation of cell-interfacing materials, as it is cyto-compatible; however, this limits the number of photoswitches appropriate for these applications. In this work, we use donor-acceptor Stenhouse adduct (DASA) functionalized polymers comprising poly(ethylene glycol)-b-poly(hexyl methacrylate) to make visible light-responsive polymersomes, and use these to encapsulate a model drug cargo. We demonstrate that release of the model cargo can be triggered using visible light when the polymersomes are loaded into poly(ethylene glycol) hydrogels. Moreover, ON/OFF switchable cargo release was demonstrated by modulating the light stimulation of the hydrogel. We envisage this could be used to dynamically modulate hydrogel properties in clinically relevant applications for controlled delivery of small molecule therapeutic agents, such as advanced in vitro tissue models and implantable drug-eluting scaffolds.

In this work, we investigated the depolymerization behavior of bromine-terminated poly(isopropenylboronic acid pinacol ester) [poly(IPBpin)] by copper catalyst in comparison with poly(methyl methacrylate) (PMMA), whose depolymerization behaviors have been extensively studied. Halogen-terminated poly(IPBpin)s were precisely synthesized via copper-mediated reversible deactivation radical polymerization with a bromide initiator. In the presence of a copper catalyst, the IPBpin polymers underwent depolymerization to regenerate the monomer (i.e., IPBpin) at temperatures below 100°C, in contrast to the inert behavior of bromine-terminated PMMA under the same conditions. The ceiling temperature was determined to be 76°C (1.0 M), which was much lower than that of PMMA (202°C, 1.0 M). Notably, despite exhibiting superior depolymerizability to PMMA, the IPBpin polymers showed comparable or even higher thermal stability.

Reversible sol-gel transitions are difficult to achieve in conventional water-swollen hydrogels in open aqueous environments, because polymer chains dissolve or diffuse once the network disassembles. Here, we present a proof-of-concept to overcome this limitation by introducing a water-immiscible and non-cytotoxic ionic liquid (IL) phase that confines polymer networks and prevents dissolution during reversible phase transitions. We report a photoreversible ion gel that crosses the rheological boundary (tan δ ∼ 1) under light, enabling reversible sol-gel switching within this closed IL environment. The material integrates an ABC triblock copolymer, P(AzoAm-r-NIPAm)-b-PBuA-b-PSt, with a solvent-quality-tunable blend of non-cytotoxic ILs ([P4,4,4,1][TFSI]/[P8,8,8,8][TFSI]). The photoresponsive A-block, P(AzoAm-r-NIPAm), exhibits a polarity-dependent solubility change with the cis/trans isomerization of azobenzene, providing a reversible light-controlled self-assembly. Time-resolved rheology confirmed repeated crossings of tan δ = 1 under alternating UV-vis illumination at 52°C. The switching mechanism is governed by the lifetime of reversible junctions, consistent with transient network theory. In addition, hMSCs adhered to and spread on the ion gel at 37°C, indicating the cytocompatibility of the ion gel itself. This light-programmable, water-immiscible ion gel has the potential to provide a reversible liquid-solid mechanical cue for next-generation mechanobiology.