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Transparent polymeric materials withhigh ductility and antistaticproperties have attracted much attention. A room temperature ionicliquid (IL), tributyl(methyl)ammonium bis(trifluoromethane)sulfonylimide([tbmam+][Tf2N–]), was integratedinto polycarbonate (PC), to fabricate optically transparent antielectrostaticcomposites by melt processing. The morphology and physical propertiesof the composites were investigated. Differential scanning calorimetryand dynamic mechanical analysis indicated the depression of the glasstransition temperatures of the PC/IL composites, compared with thatof neat PC. This indicated the interaction between PC and the IL.Transmission electron microscopy indicated that the IL was highlycompatible with PC, at low IL loadings. This resulted in enhancedantielectrostatic properties, and significantly improved elongationat break of the PC/IL composites. The PC/IL composites maintainedthe high transmittance of PC. In addition, the PC/IL composites withhigh clearance and antielectrostatic properties could be achievedby large-scale continuous melt extrusion, indicating that the methodto fabricate both optically transparent and antielectrostatic compositeis feasible for industrial application. [ABSTRACT FROM AUTHOR]

The poly(l-lactic acid)/poly(oxymethylene)(PLLA/POM)blends have been prepared by simply melt blending. The phase diagram,miscibility, glass transition temperatures, and physical propertieshave been investigated systematically. The PLLA/POM blends exhibittypical lower critical solution temperature (LCST) behaviors. PLLAand POM are miscible in the melt state at low temperature and becomephase-separated at elevated temperatures. It was found that the weakinteractions between the carboxyl groups of PLLA and methylene groupsof POM (weak C–H...O hydrogen bonding) account forthe miscibility of the two components. Although the PLLA/POM blendsare homogeneous at the melt state in the miscible temperature region,two distinct glass transition temperatures are observed for the allblends when quenched from the homogeneous state. More surprisingly,both POM and PLLA exhibit the apparent glass transition temperature(Tg) depression in the blends, comparedwith Tgs of the neat polymers. The behaviorsare totally different from other reported miscible or partially misciblepolymer blends, in which Tgs shift toeach other or merge into one glass transition temperature. The investigationindicates that the crystallization of POM in the blend induces thephase separation of PLLA/POM blends and forms novel morphologies withthe interpenetrated (cocontinuous) PLLA and POM phases. The doubleglass transition temperature depression of both PLLA and POM in theblends originates from the mismatch thermal shrinkage during coolingdown from the high temperature. Moreover, we observed the improvedductility of the PLLA/POM blends as compared with the neat PLLA andPOM, which has been attributed to higher molecular mobility due tothe glass transition temperature depression for both PLLA and POMin the blends. [ABSTRACT FROM AUTHOR]

The impact of pristine multiwalled carbon nanotubes (MWCNTs),anionic liquid (IL), 1-butyl-3-methylimidazolium hexafluorophosphate[BMIM][PF6], and the ionic liquid-modified MWCNTs (IL-MWCNTs)on the crystallization behavior of melt-crystallized poly(vinylidenefluoride) (PVDF) has been investigated. Pristine MWCNTs accelerate crystallization of PVDF as an efficient nucleation agent, while theformed crystals are mainly nonpolar α crystal form with fewpolar β crystals. Incorporation of only ionic liquid resultsin depression of the PVDF melt crystallization rate due to the miscibilityof IL with PVDF but leads to a higher content of polar crystals (βand γ forms) than MWCNTs. The ionic liquid and MWCNTs show significantsynergetic effects on both the nucleation and the formation of polarcrystals for PVDF by melt crystallization. Addition of IL-MWCNTsnot only improves the MWCNTs dispersion in PVDF matrix but also increasesthe overall crystallization rate of PVDF drastically. More important,the melt-crystallized PVDF nanocomposites with IL-MWCNTs show 100%polar polymorphs but no α crystal forms. To the best of ourknowledge, this is the first report on the achievements of full polarcrystal form in the melt-crystallized PVDF without mechanical deformationor electric field. The IL to MWCNTs ratio and the IL-MWCNTs loadingcontent effects on the crystallization behavior of PVDF in the nanocompositeswere also studied. It is considered that the specific interactionsbetween >CF2with the planar cationic imidazolium ringwrapped on the MWCNTs surface lead to the full zigzag conformationsof PVDF; thus, nucleation in polar crystals (β and γforms) lattice is achieved and full polar crystals are obtained by subsequent crystal growth from the nuclei. [ABSTRACT FROM AUTHOR]

Humidity sensors have broad applications in health monitoring, environmental protection and human-machine interface, and robotics. Here, we developed a humidity sensor using alkali oxidation method to grow in situ TiO 2 nanowires on two-dimensional Ti 3 C 2 MXene. With an order of magnitude larger surface area compared to pure Ti 3 C 2 or TiO 2 materials, the urchin-like Ti 3 C 2 /TiO 2 composite demonstrates a record high sensitivity in a low relative humidity (RH) environment (∼280 pF/% RH from 7% RH to 33% RH). Complex impedance spectroscopy and Schottky junction theory were employed to understand the underlying sensing mechanisms of the Ti 3 C 2 /TiO 2 composite under various humidity conditions. We demonstrate the application of humidity sensors made with the Ti 3 C 2 /TiO 2 composite for noncontact detection of the presence of various liquids as well as human fingers.

Two-dimensional (2D) MXenes have recently been shown to be promising for applications in anticancer photothermal therapy (PTT), owing to their outstanding photothermal performance. However, as with the other inorganic 2D nanomaterials, the MXene-based nanoplatforms lack the appropriate biocompatibility and stability in physiological conditions, targeting capability, and controlled release of drug, for cancer therapy. Fabricating a smart MXene-based nanoplatform for the treatment of cancer therefore remains a challenge. In this work, composite hydrogels based on cellulose and Ti 3 C 2 MXene, were synthesized for the first time. We have shown that the cellulose/MXene composite hydrogels possess rapid response near-infrared-stimulated characteristics, which present as a continuous dynamic process in water. As a result, when loaded with the anticancer drug doxorubicin hydrochloride (DOX), the cellulose/MXene hydrogels are capable of significantly accelerating the DOX release. This behavior is attributed to the expansion of the pores within the three-dimensional cellulose-based networks, triggered by illumination with an 808 nm light. Capitalizing on their excellent photothermal performance and controlled, sustained release of DOX, the cellulose/MXene hydrogels are utilized as a multifunctional nanoplatform for tumor treatment by intratumoral injection. The results showed that the combination of PTT and prolonged adjuvant chemotherapy delivered using this nanoplatform was highly efficient for instant tumor destruction and for suppressing tumor relapse, demonstrating the potential of the nanoplatform for application in cancer therapy. Our work not only opens the door for the fabrication of smart MXene-based nanocomposites, along with their promising application against cancer, but also paves the way for the development of other inorganic 2D composites for applications in biomedicine.

Herein, we report a simple strategy to synthesize quasi-block graft copolymers using the binary phase structure of semicrystalline polymers as the template. An unsaturated ionic liquid, 1-vinyl-3-butylimidazolium bis (trifluoromethylsulfonyl) imide ([VBIm] [TFSI]), is thermodynamically miscible with poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-co-HFP)) in solution. The solidification of P(VDF-co-HFP)/[VBIm] [TFSI] blend leads to the expelling of ILs from the crystalline region and the ILs are only located in the amorphous region. The electron-beam irradiation (EBI) at the solid state of the blends results in the locally grafting of the ILs onto the polymer blocks in the amorphous region, while the EBI does not affect the chemical structure of the crystalline region. Therefore, the quasi-block graft copolymers were achieved with IL-grafted blocks segregated by the unmodified blocks. The achieved block copolymers can be microphase separated into the various nanostructures, as the block copolymers with well-defined structure, upon varying the grafting ratios. The microphase separated quasi-block grafted copolymers exhibit excellent mechanical properties and good electrical properties. The elongation at break is 480% and the stress at break is as high as 30 MPa for the sample with the lamellar-like structure having the grafting ratio of 45.4 wt%.

Novel anti-static nanofibers based on blends of poly(vinylidene fluoride) (PVDF) and a room-temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], were fabricated using an electrospinning approach. The effects of the RTIL on the morphology, crystal structure, and physical properties of the PVDF nanofibers were investigated. Incorporation of RTIL leads to an increase in the mean fiber diameter and the rough fiber surface of the PVDF/RTIL composite nanofibers compared with the neat PVDF nanofibers. The PVDF in the PVDF/RTIL nanofibers exhibits an extremely high content (almost 100%) of β crystals, in contrast to the dominance of PVDF γ crystals in bulk melt-blended PVDF/RTIL blends. Nonwoven fabrics produced from the electrospun PVDF/RTIL composite nanofibers show better stretchability and higher electrical conductivity than those made from neat PVDF without RTIL, and are thus excellent antielectrostatic fibrous materials. In addition, RTIL greatly improved the hydrophobicity of the PVDF fibers, enabling them to effectively separate a mixture of tetrachloromethane (CCl4) and water. The extremely high β content, excellent antielectrostatic properties, better stretchability, and hydrophobicity of the present PVDF/RTIL nanofibers make them a promising candidate for micro- and nanoscale electronic device applications.