Polymer nanocomposite

About: Polymer nanocomposite is a research topic. Over the lifetime, 8977 publications have been published within this topic receiving 297599 citations.

Role of Casting Solvent on Nanoparticle Dispersion in Polymer Nanocomposites

Abstract: We investigate the influence of casting solvent on the final spatial dispersion of nanoparticles (NPs) in polymer nanocomposites (PNCs). We prepared nanocomposites of bare silica NPs and poly(2-vinylpyridine) (P2VP) by casting from two different solvents—methyl ethyl ketone (MEK) and pyridine—which are theta/good solvents, respectively, for both the polymer and the NPs. In MEK, we show that P2VP strongly adsorbs onto the silica surface to create a temporally stable bound polymer layer. The resulting “hairy” particles are sterically stabilized against agglomeration, and thus good NP dispersion in PNCs is always achieved, independent of P2VP molecular weight, concentration, or NP loading. On the contrary, in pyridine, P2VP does not adsorb on the silica NPs. The phase behavior in this case is thus governed by a subtle balance among electrostatic repulsion, polymer-induced depletion attraction, and the kinetic slowdown of diffusion-limited NP aggregation. While there is little remnant solvent in the dry PNC, ...

Polymer nanocomposite nanomechanical cantilever sensors: material characterization, device development and application in explosive vapour detection

Abstract: This paper reports an optimized and highly sensitive piezoresistive SU-8 nanocomposite microcantilever sensor and its application for detection of explosives in vapour phase. The optimization has been in improving its electrical, mechanical and transduction characteristics. We have achieved a better dispersion of carbon black (CB) in the SU-8/CB nanocomposite piezoresistor and arrived at an optimal range of 8?9?vol% CB concentration by performing a systematic mechanical and electrical characterization of polymer nanocomposites. Mechanical characterization of SU-8/CB nanocomposite thin films was performed using the nanoindentation technique with an appropriate substrate effect analysis. Piezoresistive microcantilevers having an optimum carbon black concentration were fabricated using a design aimed at surface stress measurements with reduced fabrication process complexity. The optimal range of 8?9?vol% CB concentration has resulted in an improved sensitivity, low device variability and low noise level. The resonant frequency and spring constant of the microcantilever were found to be 22?kHz and 0.4? N?m ? 1 respectively. The devices exhibited a surface stress sensitivity of 7.6?ppm (mN?m ? 1) ? 1 and the noise characterization results support their suitability for biochemical sensing applications. This paper also reports the ability of the sensor in detecting TNT vapour concentration down to less than six parts per billion with a sensitivity of 1? mV/ppb.

A temperature sensor based on a MWCNT/SEBS nanocomposite

Abstract: The fabrication of a temperature sensor based on multi-walled carbon nanotubes (MWCNTs)/styrene-b-(ethylene-co-butylene)-b-styrene (SEBS) triblock copolymer composite is reported. The device was realized by drop casting 10 μl of a MWCNTs dispersion in a toluene solution of SEBS onto gold electrodes fabricated onto a polyimide support. Thermogravimetric and electrical resistance measurements highlighted a good reproducibility of film composition and sensing properties. A negative temperature coefficient with an absolute value comparable to the highest values in metals was measured when a substantial amount of MWCNTs was incorporated into the nanocomposite (40% by weight), and a five-fold increase was observed close to the percolation threshold. Though such sensitivity seems to be partly lost after the first heating, the results allowed us to be optimistic about the feasibility of realizing nanocomposite films with temperature sensitivities comparable to that of common thermistors in the range 20–60 °C.

Tailored magnetic and magnetoelectric responses of polymer-based composites

Abstract: The manipulation of electric ordering with applied magnetic fields has been realized on magnetoelectric (ME) materials; however, their ME switching is often accompanied by significant hysteresis and coercivity that represents for some applications a severe weakness. To overcome this obstacle, this work focuses on the development of a new type of ME polymer nanocomposites that exhibits a tailored ME response at room temperature. The multiferroic nanocomposites are based on three different ferrite nanoparticles, Zn0.2Mn0.8Fe2O4 (ZMFO), CoFe2O4 (CFO) and Fe3O4 (FO), dispersed in a piezoelectric copolymer poly(vinylindene fluoride-trifluoroethylene) (P(VDF-TrFE)) matrix. No substantial differences were detected in the time-stable piezoelectric response of the composites (∼ −28 pC·N1–) with distinct ferrite fillers and for the same ferrite content of 10 wt %. Magnetic hysteresis loops from pure ferrite nanopowders showed different magnetic responses. ME results of the nanocomposite films with 10 wt % ferrite c...