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[Display omitted] • Flexible polymer PENGs were prepared with interface-engineered PVDF/CNTs nanofibers. • PVDF- g -MA stabilized electrospinning flow to yield defect-free composite nanofibers. • Interfacial anchoring of PVDF- g -MA promoted electroactive β -phase in PVDF matrix. • A small amount of PVDF- g -MA boosted piezoelectric outputs (10.6 V, 3.15 µW/cm2) • Our strategy enhanced PENG with preserved flexibility avoiding excessive filler use. Polymeric piezoelectric nanogenerators (PENGs) hold great promise for flexible energy harvesters and self-powered sensors. However, achieving high piezoelectricity in inherently piezoelectric polymers while maintaining their flexibility remains a challenge. Herein, we propose a simple yet effective approach to fabricate flexible and cost-effective PENGs based on interface-engineered composite nanofibers of poly(vinylidene fluoride) (PVDF)/carbon nanotubes (CNTs) using electrospinning. Our strategy involves the incorporation of a tailor-made interfacial coupling agent, maleic anhydride grafted PVDF (PVDF- g -MA), onto PVDF/CNTs interfaces. This mild interface-engineering strategy not only promotes interfacial interactions within composites but also stabilizes electrospinning flow jets, yielding defect-free nanofibers. More importantly, the interfacial anchoring of PVDF- g -MA molecules promotes the preferential crystallization of electroactive β -phase within PVDF matrix. By incorporating a small quantity of PVDF- g -MA (up to 1.0 wt%), our approach significantly enhances piezoelectric outputs while preserving flexibility. This eliminates the need for excessive nanofiller usage that can sacrifice the flexibility associated with conventional methods. Remarkably, the resulting composite nanofiber-based PENGs exhibit excellent piezoelectric performance, generating high output voltages (10.6 V) and remarkable power density (3.15 µW/cm2) under tiny force stimuli. Our findings open new avenues for efficient and scalable fabrication of polymeric piezoelectric nanogenerators for flexible and wearable energy harvesting and self-powered sensing applications. [ABSTRACT FROM AUTHOR]

The advantages of segregated conductive polymer composites are greatly hampered owing to its limited preparation technology, which seriously relies on hot compression with low efficiency. The plunger type injection molding (PTIM) is employed to fabricate segregated carbon nanotubes (CNTs)/high density polyethylene (HDPE)/ultra-high molecular weight polyethylene (UHMWPE) composites in this paper, which lowers the production cycle by 45%, compared with the conventional hot compression. The morphology and conductive properties are investigated in detail. Graceful segregated conductive network and a very low percolation threshold (0.45 vol%) of the polymer composites have both been achieved. The present processing technique with short production cycle provides a fancy idea to realize segregated conductive polymer composite in mass production. [ABSTRACT FROM AUTHOR]

A novel approach, i.e. manipulating the size of incorporated polymer matrix particles, was proposed to tune the positive temperature coefficient (PTC) characteristics of carbon nanotubes (CNTs)/polypropylene (PP) composites with a segregated microstructure. For the conductive properties of CNTs/PP composites, the percolation threshold decreased from 1.32 vol% to 0.44 vol% when the matrix particle size enlarged from 20 to 1200 µm, showing an inverse correlation effect. The controllable PTC characteristics in resistivity are attributed to the microstructure development of conductive pathways and the heat-induced volume expansion of polymer matrix particles. An extremely high PTC material has also been achieved through this method. The present work provides an effective route to acquire a tunable temperature-resistivity sensor. [ABSTRACT FROM AUTHOR]

Resistivity–temperature characteristics of conductive multi-walled carbon nanotubes (MWCNT)/epoxy (EP) composite were studied during a heating-cooling run (HCR) with different top test temperatures. The values of R e (room-temperature resistance at the end of a HCR) decrease with increasing the top test temperature. The fluctuation-induced tunneling conduction (FITC) and the hysteresis effect developing in MWCNT/EP composite are responsible for this fascinating phenomenon. In order to understand this result further, resistivity–temperature characteristic at different cooling rates was studied. The values of R e also decrease with rising the cooling rate. This paper provides an effective approach to acquire a tunable temperature sensor. [ABSTRACT FROM AUTHOR]