Macromolecular Chemistry and Physics最新文献

With the rapid development of the internet of things, the simple preparation of sensors has become a challenge. The present work presents the simple preparation of flexible sensors by using the fused deposition modeling (FDM) 3D printing combined with the microwave radiation-assisted treatment of the thermoplastic polyurethane (TPU) with carbon nanotubes (CNTs) as conductive fillers to create the flexible sensors. The as-prepared TPU/CNT composites exhibit the 7.27 MPa tensile strength and 401% elongation at break, similar to those of the pure TPU. After 200 tensile cycles, the TPU/CNT composites can still stably convert pressure into electrical signals, which can be used as flexible sensors with high sensitivity (0.879 kPa⁻¹). In addition, shoe insoles and finger cover with sensing performance are fabricated through the FDM 3D printing technology, demonstrating the potential of the sensors to monitor human gait, finger straightening, and bending movements. The as-proposed method involves the embedding CNTs as conductive fillers on the surface of TPU to form the TPU/CNT composite conductive layers on the surface of TPU, which is beneficial for maintaining the elasticity of the polymer matrix. The challenges in preparing stable, low-cost, and scalable flexible sensors and highlights of the advantages of 3D printing technology in manufacturing flexible piezoresistive sensors are also deeply discussed.

Solid-state cross-polarization magic angle spinning (CPMAS) ¹³C NMR is employed to examine the morphological factors that contribute to the enhanced hole mobility observed in poly(3-hexylthiophene) (P3HT) by the introduction of electrically inert poly(styrene) (PSt). Chain mobilities of crystalline and amorphous phases in the P3HT domain are evaluated utilizing T₁^C (¹³C spin-lattice relaxation time in the laboratory frame). The crystallinity of P3HT component is estimated based on the spectral editing method through T_1ρ^H (¹H spin-lattice relaxation time in the rotating frame) filtered CPMAS. Moreover, the miscibility of P3HT crystalline and P3HT amorphous domains is estimated. These results suggest the formation of the rigid amorphous (short-range ordered amorphous) in a block copolymer (P3HT-block-PSt). An increase in the proportion of the crystallite and proximate presence of each crystallite in a blend sample of P3HT with PSt (P3HT-blend-PSt) are also indicated. Enhanced mobility is attributed to the larger portion of rigid amorphous domain for P3HT-block-PSt, and to higher crystalline content for P3HT-blend-PSt.

The development of conjugated polymer–based water-soluble nanoparticles for near-infrared-II (NIR-II) fluorescence (FL; 1000–1700 nm)-guided photothermal therapy holds promise in advancing cancer treatment. However, excessive nonradiative decay leads to almost complete quenching of conjugated polymers’ fluorescence. Therefore, a critical challenge is to suppress nonradiative decay while maintaining high-quality fluorescence imaging and excellent photothermal conversion efficiency. In this study, a series of NIR-II-conjugated polymers with aggregation-induced emission (AIE) effects are designed and synthesized using the Stille coupling reaction. The dual enhancement strategy of modulating the AIE units and introducing non-conjugated backbone into the polymer backbone resulted in BCT1 with a high αAIE value of 3.27. BCT1 nanoparticles exhibit excellent NIR-II fluorescence, a high photothermal conversion efficiency of 70.51%, and a tenfold enhancement in fluorescence compared with BT1. Both in vitro and in vivo experiments validated their good biocompatibility and outstanding performance in NIR-II fluorescence imaging for accurately determining the location of tumors. This study provides a novel strategy and method for designing and developing multifunctional conjugated polymers for NIR-II fluorescence imaging–guided photothermal therapy.

To solve the downhole problems correlated with clay hydration swelling and dispersion under high-temperature conditions, a 1-aminoethyl-3-vinylimidazolium bromide ([NVim]Br) and a [NVim]Br/acrylamide copolymer (poly([NVim]Br-co-AM)) are synthesized and used as inhibitors. The molecular structures of [NVim]Br and poly([NVim]Br-co-AM) are characterized by FT-IR and ¹H-NMR. The inhibition properties of [NVim]Br and poly([NVim]Br-co-AM) are evaluated by free swelling and dispersion tests, linear swelling, hot roll recovery experiments and thermogravimetric analyses.The inhibition mechanisms were revealed by X-ray diffraction, zeta potential, wettability analysis and ESEM observation. The results showed that both [NVim]Br and poly([NVim]Br-co-AM) has significantly superior inhibition performance compared with the common inhibitors KCl, polyether amine D230 and polyquaternium-7. Both [NVim]Br and poly([NVim]Br-co-AM) can resist 250 °C. [NVim]Br performed excellently in inihibiting both crystalline and osmotic swelling, which depended on the strong electrostatic adsorption and hydrogen bonds of imidazole cations and primary amine in [NVim]⁺. Poly([NVim]Br-co-AM) exerted excellent inhibition by minimizing osmotic swelling, reducing hydrophilicity and increasing clay bonding. The results are important for understanding the rational design of novel efficient inhibitors for drilling high-temperature shale formation.

Identification of suitable polymeric materials to fabricate microneedles (MNs) for the collection of interstitial fluid (ISF) is a challenge. Here, characterization of different carrageenan-biopolymer composites for MN patch fabrication intended for ISF collection is reported. Systematic oscillatory rheological studies of composites containing iota-carrageenan mixed with alginate, gelatin, or pectin are performed to determine the linear viscoelastic region, gel point, tan delta, complex viscosity, and flow transition index. A polynomial equation is derived by relating flow transition index of biopolymer composites and compression strength of fabricated MNs. The biopolymer composite of iota-carrageenan and gelatin at 2% and 14%, respectively, and CaCl₂ crosslinker (80 mm) shows the greatest compression strength sufficient for MNs insertion into the excised porcine skin. MNs swell up on application in an agarose gel model and the ex vivo excised porcine skin model to collect 36 ± 5 and 14 ± 1 µL of fluid within 10 min, respectively. Taken together, it is demonstrated that rheological analysis can be performed to select suitable polymer composites that possess sufficient strength for the skin insertion and swellability for ISF collection.