Sputter coaters

Figure Bl.17.8. Iron oxide particles coated with 4 nm of Pt in an m-planar magnetron sputter coater (Hennann and Mtiller 1991). Micrographs were taken in a Hitachi S-900 in-lens field emission SEM at 30,000 primary magnification and an acceleration voltage of 30 kV. Image width is 2163 nm.

Liquid C02 from a siphon-tube tank is introduced into the chamber and used to replace 100% of the ethanol in the specimen. After the ethanol has been totally replaced by the C02, the critical point drying chamber (CPD) is brought above the critical point. The temperature is kept above the critical point, while the gaseous C02 is vented from the chamber. The process is finished when the CPD is returned to atmospheric pressure. After critical point drying, the specimen should be totally dry and it is ready to be introduced to the vacuum system of the sputter coater and SEM (Dykstra, 1993 Hayat, 1978). 

Dehydrate in a graded alcohol series series (30%, 50%, 70%, 90%, 100%), for 100% use in 200 proof alcohol Freon or amyl acetate (use a graded series, e.g., 1 3, 1 2, 1 1 Freon/alcohol and then pure Freon) Critically point dry using liquid C02 soaks and flushes Mount on aluminum stubs using silver paint or double-stick tape0 Sputter coat with gold/palladium in a sputter coater flushed with argon... 

Scanning Electron Microscopy, An ISI model Super II (International Scientific Instruments Inc., Milpitas, CA) scanning electron microscope was used for morphology study (Labtech, Fairfield, NJ). Powder was properly loaded on specimen stub via a double stick tape. Samples were coated with 60% gold and 40% palladium for 6 min at 100 to 200 mtorr in a sputter coater. 

According to the standard procedure adopted, the suspension was shaken at 25 °C for 72 hours, and centrifuged (10,000 x g) and the remaining solid was drained and dried under vacuum at room temperature. The dried adsorbed material was powdered and sprinkled on the sample holder of a Zeiss DSM 960 Digital Scanning Microscope which was then submitted to gold sputtering with a Sputter Coater Balzers SCD 050. 

An Emitech sputter coater model K550 is used to deposit the gold thin film working electrode. 

Samples of microspheres were mounted on aluminum specimen mounts by means of double-faced tapes. The microspheres were fractured with razor blades to expose the internal matrix. The samples were then coated with approximately 125 of gold by pulsing the sputter coater to avoid the possibility of artifact caused by heat generation. Secondary emissive scanning electron microscopy was performed with an Amray 1600 Turbo scanning electron microscope. 

Representative freeze-dried samples were mounted on aluminum stubs using conductive paint, coated with gold/palladium (60 U0) in a Technics sputter coater and examined in an ETEC Autoscan scanning electron microscope at 10 kV. 

For SEM examination the same amount of the starting suspension was filtered on a polycarbonate filter, 0.2 /am pore size and 25 mm diameter, placed on a backing cellulosic filter of 1.2 /am pore size, in order to facilitate a more uniform distribution of particles on the filter. A small portion of the particles-laden filter was then mounted on SEM stubs by double sided sticky tape and then coated by gold of about 300 nm thick in a sputter coater [11]. 

The physical structures of spray-dried and freeze-dried amorphous and crystalline (humidified over 54.5, 65.6 and 76.1% RVP for 144 h for spray-dried and 72 h for freeze-dried) lactose were viewed by SEM (JSM-840, Tokyo, Japan). Small amounts of samples were mounted on SEM specimen stubs by using double-sided adhesive tape. The mounted samples were then coated with gold in a sputter coater (Edwards sputter coater, Sussex, UK) under high vacuum. The coated samples were viewed with SEM at 20 KV in the secondary electron mode. The samples were systematically viewed at 500 to 10,000 X magnifications. 

For SEM small wood pieces (0.5 X 0.5 X 0.5 cm) were removed from the sample material with a razor blade and then mounted on aluminum stubs with double-sided cellophane tape. After coating with gold (Polaron Sputter Coater), samples were examined by SEM (Cambridge S150) at 10 or 20 kV. 

The dried membranes are then broken in liquid nitrogen. A sample is then cut and placed on mounting cylinder with the cracked surface exposed for observation. It is coated with a gold-platinum sputter coater and observed using a scanning electron microscope. 

For observing structural preservation of freeze-dried cells at greater details than provided by optical microscopy, a JOEL JSM 35 scanning electron microscope (JEOL Ltd., Tokyo, Japan) was used in this study. Eor improving the quality of SEM images, the freeze-dried cells were coated with a thin layer of Au/Pd in a sputter coater (Ted Pella Inc., Redding, CA, USA). 

Place the ITO slide with the sample in the Quorum Technologies SC7640 sputter coater. Press the start sequence button to pump down, flush with argon, further pump down the vacuum chamber, and leak in argon until the pressure reaches 0.1 mbar (all done automatically). 

---