Recently, the room-temperature phosphorescence
(RTP) properties
of carbon dots (CDs) have attracted significant interest. However,
the regulation of RTP emission faces great challenges because of untunable
emissive lifetime and wavelength. Here, ultrahigh-yield acrylamide-based
N-doped carbonized polymer dots (AN-CPDs) with ultralong RTP lifetime
are synthesized by a one-step hydrothermal addition polymerization
and carbonization strategy. The RTP lifetime and wavelength of the
proposed AN-CPDs can be regulated by changing the carbonization degree.
Thus, the AN-CPDs’ RTP lifetimes are in the range of 61.4–466.5
ms, while the RTP emission wavelengths vary from 485 to 558 nm. Further
experiment and theoretical calculation proved that RTP can be attributed
to the polymer/carbon hybrid structure and nitrous functional groups
as the molecular state related emission centers. Supramolecular cross-linking
in the aggregated state is vital for the RTP emission of the AN-CPDs
by restricting the nonradiative transition of the triplet excitons.
AN-CPDs of different RTP lifetimes can be applied to time-resolved
multistage information encryption and multistage anticounterfeiting.
This work facilitates the optical regulation and application potential
of CDs and provides profound insights into the effect of the polymer/carbon
hybrid structure on the properties of CDs.
Electrofluorochromism has attracted great attention due to the intelligence optoelectronic and sensing applications. The intrinsically switchable fluorophores with high solid-state fluorescence are regarded as key for ideal electrofluorochromic materials. Here, we reported an AIE-active polyamide with diphenylamine and tetraphenylethylene units, showing high fluorescence quantum yield up to 69.1% for the solid polymer film and stable electrochemical cycling stability. The polyamide exhibited reversible color and emission switching even in hundreds of cycles, and the fluorescence on/off contrast ratio was determined up to 417, which is the highest value to our knowledge. Furthermore, as the response time is vital for the real-life applications, to speed up the response of electrofluorochromism, a porous polymer film was readily prepared through a facile method, notably exhibiting high fluorescence contrast, long-term stability and obviously improved response, due to the sharply increased surface area. Therefore, the AIE-functionalization combining the porous structure strategy will synergistically and dramatically improve the electrofluorochromic performance, which will also promote their practical applications in the near future.
Electrofluorochromic (EFC) materials
have aroused great interest
owing to their interesting ability of tuning fluorescence in response
to the applied potential. However, some crucial characteristics, such
as response speed, fluorescence contrast, and switching stability,
are still not well realized to meet the requirements of practical
applications. Herein, we designed and synthesized a novel polyamide-bearing
aggregation-induced emission (AIE)-active tetraphenylethylene (TPE)
and a highly conjugated triphenylamine (TPA) pendant group. The rational
combination of the highly conjugated TPA and TPE caused the resultant
polymer to exhibit highly integrated electrochromic (EC) and EFC performances
including multiple color-changing (colorless to green to blue), fast
response speed (1.8/1.1 s for EC and 0.4/2.9 s for EFC process), high
fluorescence contrast (82 at the duration time of 20 s), and excellent
long-term stability over 300 cycles. The strategy of AIE functionality
by combing a highly conjugated redox unit demonstrates a synergistic
effect to prepare high-performance emission/color dual-switchable
materials, greatly promoting their applications in sensors, smart
windows, and displays.
Molluscan shells are fascinating examples of highly ordered hierarchical structure and complex organic-inorganic biocomposite material. However, their anti-wear properties were rarely studied especially in the perspective of biological coupling. So in the current study three typical shells, Scapharca subcrenata, Rapana venosa and Acanthochiton rubrolineatus, were selected as coupling models to further study their anti-wear properties. Stereomicroscope and scanning electron microscopic observations showed that all these three shells had specific surface morphologies and complicated section microstructures. Importantly, a special structure, pore canal tubules, was discovered in the shells of Scapharca subcrenata and Acanthochiton rubrolineatus, which probably contributed most to their anti-wear properties. X-ray diffraction and micro-Vikers hardness tester were further adopted to analyze the phase compositions and micro-hardness of the shells. The measured results demonstrated that aragonite was the most extensive phase present in the shell, and possesed a relatively high micro-hardness. In this paper, the shells were described in details in morphology, structure and material with emphasis on the relationship with anti-wear property. The study revealed that the selected seashells possess distinct anti-wear properties by complicated mechanisms involving the integrated functions of multiple biological coupling elements, and this would provide inspiration to the design of new bionic wear resistance components. molluscan shell, wear resistance, bionic, biological coupling, coupling element Citation:Tian X M, Han Z W, Li X J, et al. Biological coupling anti-wear properties of three typical molluscan shells-Scapharca subcrenata, Rapana venosa and Acanthochiton rubrolineatus.
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