71 cm-1 due to the C-H bending vibration. As given in Figure 3b, these characteristic vibration and bending features reappear in the FTIR spectrum of the PEO-PPO-PEO-capped ZnO-Au nanoparticles, but blueshifting to find more the positions of approximately 1,115.63 cm-1 for the C-O-C stretching vibration and approximately 1,625.26 cm-1 for the C-H bending vibration

[27, 28], respectively. Evidently, the vibration and bending shapes and absorption intensities vary between the pure PEO-PPO-PEO molecules and the PEO-PPO-PEO-covered ZnO-Au nanoparticles. Both blue-shifting and shape change in the C-O-C stretching and C-H bending modes may be attributed to the interactive coordination of the oxygen atoms in the PEO-PPO-PEO main chains

to the Au and Zn atoms in the hybrid nanostructure [27, 28, 31]. Consequently, the observation provides strong evidence that the PEO-PPO-PEO molecules are coated onto the surface of the ZnO-Au nanoparticles, as the redundant Microbiology inhibitor PEO-PPO-PEO molecules were removed by the washing procedure. As a result of such PEO-PPO-PEO lacing, these PEO-PPO-PEO-ZnO-Au nanoparticles turn out to be both hydrophobic and hydrophilic, which are entitled a bi-phase dispersible property intended for an easy transport of the nanoparticles between non-polar and polar solvents without further surface modification, as demonstrated in the study on the optical properties of the nanoparticles in the subsequent sections [17]. Figure 3 FTIR spectra of (a) the pure PEO-PPO-PEO polymer and (b) the PEO-PPO-PEO-laced ZnO-Au hybrid nanoparticles. The optical properties of the polymer-laced ZnO-Au Amisulpride hybrid nanoparticles were evaluated by UV-visible absorption spectroscopy and photoluminescence (PL) spectrometry. As mentioned above,

the nanoparticles can be directly dispersed either in an organic or an aqueous medium without further surface decoration. Figure 4 shows the UV-vis spectra of the ZnO-Au nanoparticles dispersed in hexane (a), water (b), and ethanol (c), together with those of Au (d) and ZnO (e) nanocrystals in similar sizes dispersed in hexane. Clearly, there are two kinds of absorption bands, one from ZnO and the other from the surface plasmon resonance (SPR) of the nanosized Au. In Figure 4a, the ZnO-Au nanoparticles dispersed in hexane exhibit one well-defined absorption band learn more around 356 nm, which is the most distinctive absorption of the ZnO semiconductor [12, 32], indicating a blueshift with respect to the absorption peak of the ZnO nanoparticles in hexane at the position of approximately 365 nm, as shown in Figure 4e. In contrast, the effects of solvents on the characteristic absorption band are unambiguously detected in the UV-vis spectra of the polymer-laced ZnO-Au nanoparticles dispersed in water and ethanol.