Aligned CdS nanowires (NWs) were obtained through a simple thermal evaporation process with highly active CdS nanoparticles as the evaporation source. These NWs show prominent optical waveguides behavior under a continuous-wave (CW) laser excitation. Excitation intensity-dependent photoluminescence (PL) measurements show that these NWs exhibited both broad and supernarrow stimulated emission (lasing) under intense pulse optical excitation at room temperature. Raman scattering and time-resolved PL measurements were used to investigate the optical properties. The results indicated that the stimulated emission in these NWs involves the electron-hole plasma (EHP) and Farby-Perot (F-P) optical resonant processes at room temperature.

Polylactide (PLA), a commercially available thermoplastic derived from plant sugars, finds applications in consumer products, disposable packaging, and textiles, among others. The widespread application of this material is limited by its brittleness, as evidenced by low tensile elongation at break, impact strength, and fracture toughness. Herein, a multifunctional vegetable oil, acrylated epoxidized soybean oil (AESO), was investigated as a biodegradable, renewable additive to improve the toughness of PLA. AESO was found to be a highly reactive oil, providing a dispersed phase with tunable properties in which the acrylate groups underwent cross-linking at the elevated temperatures required for processing the blends. Additionally, the presence of hydroxyl groups on AESO provided two routes for compatibilization of PLA/AESO blends:(1) reactive compatibilization through the transesterification of AESO and PLA and (2) synthesis of a PLA star polymer with an AESO core. The morphological, thermal, and mechanical behaviors of PLA/oil blends were investigated, in which the dispersed oil phase consisted of AESO, soybean oil (SYBO), or a 50/50 mixture of AESO/SYBO. The oil additives were found to toughen the PLA matrix, with significant enhancements in the elongation at break and tensile toughness values, while maintaining the glass transition temperature of neat PLA. In particular, the blend containing PLA, AESO, SYBO, and the PLA star polymer was found to exhibit a uniform oil droplet size distribution with small average droplet size and interparticle distance, resulting in the greatest enhancements of PLA tensile properties with no observable plasticization.

Elastomeric polymer films synthesized through thiol−ene chemistry, suitable in applications as coatings and adhesives due to their ease of preparation and superior physical properties, are traditionally derived from petroleum sources. Of recent interest is the exploration of sustainable alternatives for the precursors to these materials. Here, we report the synthesis of thiol−ene networks through the photoinitiated reaction between allylated plant-based phenolic acids (salicylic acid and 4hydroxybenzoic acid) and a multifunctional thiol, followed by isothermal annealing. Plant-sourced phenolic acids offer many advantages as biorenewable monomers: their rigid aromatic rings are expected to provide mechanical strength to the resulting polymers and the presence of multiple hydroxyl and carboxyl groups leads to ease of functionalization. Both phenolic acids produced networks with high degrees of homogeneity and few defects, as evidenced by narrow glass transitions and consistency of their tensile behavior with the ideal elastomer model at low-to-moderate strains. The 4-hydroxybenzoic acid based network, which had a higher cross-link density, exhibited a higher glass transition temperature, modulus, tensile strength, and elongation at break as compared to the salicylic acid based network. This work develops fundamental relationships between the molecular structure of the phenolic acids and the physical properties of the resulting networks.

Biobased epoxy resins, derived from lignin, phenolic acids, and vegetable oils, exhibited rapid degradation through hydrolysis in basic solution.

Well-crystallized Mn-doped ZnO nanowires were synthesized by a hightemperature chemical reduction method. The microscopic and macroscopic photoluminescence (PL) spectra of these Mn-doped ZnO nanowires were studied. Both the free-exciton emission band and the second-order longitude optical (2LO) phonon-assisted emission band were observed in the microscopic PL spectra. Furthermore, from the power dependent macroscopic PL spectra, the stimulated emission was observed around the 2LO phonon-assisted emission band with an increase in pump fluence, which relates to the strong excitonphonon couplings along the c-axis in these Mn-doped ZnO nanowires. The nonresonant micro-Raman scattering spectrum demonstrates the strong 2LO phonon mode, which is enhanced by Mn doping. Resonant micro-Raman scattering shows multi-LO modes, due to the strong exciton-phonon coupling via a deformation potential induced by the Mn ions in these Mn-doped ZnO nanowires. Moreover, the low-temperature UV PL band is discussed to demonstrate the activity of phonons in the Mn-doped ZnO nanowires.