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Facile synthesis of yellow emissive carbon dots with high quantum yield and their application in construction of fluorescence-labeled shape memory nanocomposite
摘要： Synthesizing carbon dots (CDs) with efficient long-wavelength emissions (i.e., yellow- to red light) generally suffer from sophisticated approaches, time-consuming process, harsh conditions, and requirement of organic solvent; also, a further limitation of the resulting CDs is relatively low quantum yield (QY) in aqueous solution. Herein, novel yellow emitting CDs (Y-CDs) with a considerable QY of 62.8% were synthesized from a precursor comprising resorcinol and o-phenylenediamine via a facile microwave method. To probe the fluorescence mechanism, another typical resorcinol-derived CDs using ethylenediamine as dopant were fabricated as well, showing strong green emission with an absolute QY of 60.6%. Spectroscopic and structural characterizations indicated that the distinct redshift of green to yellow emission depended on the dimension of conjugated sp2-domain and the content of graphitic N heavily, while the excellent QY was highly related to the low proportion of defective sp2 carbon cluster and high nitrogen content within CDs. Moreover, the Y-CDs were confirmed to be capable of introducing additional crosslinking points in poly(vinyl alcohol) (PVA) polymer, which resulted in the Y-CDs-contained nanocomposite behaving superior and tunable water-induced shape recovery performances. Importantly, since being labeled with long-wavelength emission, the responsiveness of PVA/Y-CDs composite will contribute to its versatile utilization in biology-relevant fields.
关键词： shape recovery,fluorescence mechanism,yellow emission,carbon dots,nanocomposite
更新于2025-11-14 15:23:50
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Interaction of photothermal graphene networks with polymer chains and laser-driven photo-actuation behavior of shape memory polyurethane/epoxy/epoxy-functionalized graphene oxide nanocomposites
摘要： This work demonstrates the fabrication and near infra-red laser-driven shape recovery actuation behavior of bisphenol A diglycidyl ether-functionalized graphene oxide (DGEBA-f-GO)-based polyurethane (PU)/epoxy nanocomposites. DGEBA-f-GO was synthesized as a photothermal filler by treating DGEBA with carboxylated GO in a two-step process. Homogeneously dispersed networks of the photothermal filler were engineered via covalent crosslinking between DGEBA and DGEBA-f-GO in the PU matrix. The crosslinked DGEBA-f-GO networks act as a near-infrared laser-harvesting framework for the efficient transfer of heat and trigger for shape recovery upon remote actuation. Interaction between the photo-thermal networks of DGEBA-f-GO with polymer chains was analyzed structurally, revealing that the DGEBA-f-GO networks in the nanocomposites stimulate the formation of an integrated netpoint framework in the matrix by interacting with the PU hard segment via hydrogen bonding. Consequently, the shape memory composites reinforced with GO networks showed enhanced laser-driven photo-actuation stress, as well as thermal stability, photothermal behavior, and mechanical properties.
关键词： Polyurethane,Shape recovery,Graphene oxide
更新于2025-09-12 10:27:22