Polymer Nanocomposites nanorods

Keywords Solar cells, organic photovoltaics (OPVs), quantum confinement effect (QCE), conjugated polymers, nanocomposites, blends, quantum dots (QDs), nanocrystals, nanorods, carbon nanotubes (CNTs), graphene, nanoparticles, alternating copolymers, block copolymers, exdton diffusion length, short-circuit current, open-circuit voltage, fill factor, photoconversion efficiency, in-situ polymerization... 

The emerging of nanotechnology at the end of twentieth century, many new nanomaterials have been developed such as nanoparticles, nanorods, nanowires, nanotubes, and nanoplates. By using nanomaterial as reinforcing filler and incorporating it into the polymer matrix, one can obtain polymer nanocomposite. There are many review articles and textbooks devoted to this subject (Twardowski 2007 Mittal 2010, 2013). However, the researches and discussions on nanocomposites made from LCER and nanofiller are relatively few. 

Recently, there have been a nirmber of reviews on polymer nanocomposites within this relatively broad topic, there is one specific area that has not, however, been extensively examined namely, mixtures involving nanoscopic rods and polymers. Here, we focus on nanorod polymer composites, where nanoscale rod-like particles are blended with homopolymers, polymer blends, or diblock copolymers. The spatial organization of nanorods within a polymeric material can have a dramatic effect on the composites maaoscopic properties. By elucidating these stracture-property correlations, researchers can pave the way to manipulating morphologies to aeate materials with superior performance and develop... 

To summarize, we have provided a brief review of polymer nanocomposites and the ability of nanoparticle inclusions to improve the properties of polymer materials. Furthermore, the characteristics of the nanoparticles can significantly influence the characteristics of the nanocomposite. In particular, nanorods can impart their unique properties to the polymer matrix because their high aspect ratio can facilitate stress transfer for mechanical stiffness, charge transport for improved... 

PP-g-MA) silicate nanocomposites and intercalated thermoset silicate nanocomposites for flame-retardant applications were characterised by XRD and TEM [333], XRD, TEM and FTIR were also used in the study of ID CdS nanoparticle-poly(vinyl acetate) nanorod composites prepared by hydrothermal polymerisation and simultaneous sulfidation [334], The CdS nanoparticles were well dispersed in the polymer nanorods. The intercalation of polyaniline (PANI)-DDBSA (dodecylbenzene-sulfonate) into the galleries of organo-montmorillonite (MMT) was confirmed by XRD, and significantly large 4-spacing expansions (13.3-29.6A) were observed for the nanocomposites [335],... 

Other interesting avenues are also being explored. For example, soluble 1-D coordination polymers based upon dendrimers in combination with palladium have been made 107 such soluble, low-dimensional polymers are of interest for liquid crystalline behavior and use in nanocomposites. One-and two-dimensional coordination polymers have also been used as templates for the formation of zinc oxide nanorods and... 

Nanocomposites are materials in which nanoparticles (in this case, nanorods) are dispersed in a continuous matrix. The matrix may be a polymer, nanorods, or other nanoparticles. Nanorod composites find applications in diverse areas such as efficient charge storage, removal of contaminants (e.g. surfactant) from water, emissivity control devices, and metallodielectrics, and so on. A number of methods such as electroless deposition, the sol-gel method, the hydrothermal method, solution casting, carbother-mal reduction, the template-based method, the sonochemical method, and electrospinning can be used to prepare composite nanorods. Nanorod composites are different from core-shell nanorods. In core-shell nanorods, the coating is uniform, whereas in the nanorod composite (consisting of a nanorod and a nanoparticle on a surface), fine nanoparticles are dispersed on the surface of the nanorods. Some specific examples of the preparation of nanocomposites consisting of nanorods are described below. 

Photoluminescence emission spectra of ZnO/PVA nanocomposite fihns under an excitation at 325 nm showed an intense PL emission centered around 364 nm, and a weaker and broad emission around 397 nm. ZnO/ PVA nanocomposite films prepared with OA modified ZnO nanoparticles compared to films prepared with pristine ZnO. The PL emissions observed in ZnO nanorods at 468 and 563 nm decrease considerably in intensity and are almost quenched in the composite films. The green emission in ZnO originates mainly from the deep surface traps, which can almost be removed via surface passivation by the polymer. Figure 12.13 shows the PL spectra of PVA and ZnO/PVA nanocomposite thin films for three different concentrations, 1, 2 and 3 wt% of OA modified ZnO, which gives maximum PL intensity. The composite films show intense luminescence emission centered aroimd 364 nm in the UV region and intensity of this emission peak is foimd to increase with an increase of ZnO content in the composite. The PL intensity at 397 nm is found to be more prominent in this case. The surface modification of ZnO by the polymer matrix removes defect states within ZnO and facilitates sharp near-band-edge PL emission at 364 nm. 

Using field-based models, it is more difficult to provide information about the chain conformation on the surface however, attempts have been made to understand phase separation and mechanical properties of composites. Shou et al. combined SCF/DFT techniques with lattice spring model (LSM) to study the effects of the spatial distribution and aspect ratio of particles (rods and spheres) on the mechanical properties of the composite. Buxton and Balazs combined TDGL theory for polymer blends with BD for nanorods in the simulations of nanocomposites. i A percolating network of nanorods was identified in the minority phase of a bicontinuous structure. Clancy and Gates developed a hybrid model for CNTs in a bulk poly(ethylene vinyl acetate) matrix. Molecular structures of... 

Buxton, G. A. and Balazs, A. C. 2004. Predicting the mechanical and electrical properties of nanocomposites formed from polymer blends and nanorods. Molecular Simulation 30 249-257. 

Electrical conductivity measurements have been reported on a wide range of polymers including carbon nanofibre reinforced HOPE [52], carbon black filled LDPE-ethylene methyl acrylate composites [28], carbon black filled HDPE [53], carbon black reinforced PP [27], talc filled PP [54], copper particle modified epoxy resins [55], epoxy and epoxy-haematite nanorod composites [56], polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) blends [57], polyacrylonitrile based carbon fibre/PC composites [58], PC/MnCli composite films [59], titanocene polyester derivatives of terephthalic acid [60], lithium trifluoromethane sulfonamide doped PS-block-polyethylene oxide (PEO) copolymers [61], boron containing PVA derived ceramic organic semiconductors [62], sodium lanthanum tetrafluoride complexed with PEO [63], PC, acrylonitrile butadiene [64], blends of polyethylene dioxythiophene/ polystyrene sulfonate, PVC and PEO [65], EVA copolymer/carbon fibre conductive composites [66], carbon nanofibre modified thermotropic liquid crystalline polymers [67], PPY [68], PPY/PP/montmorillonite composites [69], carbon fibre reinforced PDMS-PPY composites [29], PANI [70], epoxy resin/PANI dodecylbenzene sulfonic acid blends [71], PANI/PA 6,6 composites [72], carbon fibre EVA composites [66], HDPE carbon fibre nanocomposites [52] and PPS [73]. 

Halbach TS, Thomann Y, Mulhaupt R (2008) Boehmite nanorod-reinforced-polyethylenes and ethylene/l-octene thermoplastic elastomer nanocomposites prepared by in situ olefin polymerization and melt compounding. J Polym Sci A Polym Chem 46 2755-2765... 

Modeling Mixtures of Nanorods and Polymers Determining Structure-Property Relationship for Polymeric Nanocomposites... 

---