In this study, we evaluated the long-term antifungal effectiveness of 3 types of interior building materials (gypsum board [GB], cement board [CB], and softwood plywood [S-PW]) impregnated with thermally reduced silver nanoparticles supported by titanium dioxide (AgNPs/TiO ) under 95% relative humidity for 4 weeks. AgNPs/TiO was synthesized at 2 thermal reduction temperatures (TRTs, 120 and 200°C) with 2 different AgNP weight percentages (2 and 5 wt%). Four different silver-loading levels (SLLs, 0.025, 0.05, and 0.5 μg/cm and the critical concentration required to inhibit fungal growth on agar plates) and 3 fungal species (Aspergillus niger, Penicillium spinulosum, and Stachybotrys chartarum) were used in the experiments. Higher temperature reduced more ionic Ag to metallic Ag and increased the dispersion of Ag on TiO surface. The 200°C thermally reduced AgNPs/TiO demonstrated excellent antifungal efficiency: Mold growth was almost completely inhibited for 28 days at the low SLL of 0.5 μg/cm . Additionally, AgNPs/TiO exhibited higher antifungal activity on GB and CB than on S-PW. The stepwise regression results indicated that the TRT of AgNPs/TiO (β = -0.739 to -0.51), the SLL (β = -0.477 to -0.269), and the Ag level in the AgNPs (β = -0.379 to -0.136) were the major factors influencing antifungal activity and TRT might be the most significant one.

There are still some difficulties in injection molding a super thin plate with micro through holes. Nozzle or filter plates are some examples of typical products. Conventional processes to manufacture nozzle plates of ink jet printer heads are electroplating or laser machining. In order to reduce the production cost and improve the performance of nozzle plates, a new approach, micro injection molding, is introduced to manufacture nozzle plates in this study. The micro mold was made by integration of the LIGA and M-EDM technology to improve the positioning and alignment accuracy. After assembling the micro mold, micro injection molding technique was applied to produce four nozzle plates in one shot. There are sixty micro through-holes on each plate and their diameters have been inspected and met the specification, 101 ± 1 microns, under a proposed vario-thermal molding process. The flow hesitation problem for molding a thin film of 50 microns was then solved. Experimental and simulation results indicated that the most significant factor for molding these nozzle plates is the initial mold temperature. This work recommends that the best initial mold temperature for molding such a thin film with the nozzle array is about 150°C for PP. The manufacturing procedures proposed here are believed to be more accurate and economical, and can be applied to mold similar micro parts.