Poly electron micrograph

Figure C2.11.2. A scanning electron micrograph showing individual particles in a poly crystalline alumina powder.

Figure 20 A typical scanning electron micrograph of the macroporous uniform poly(styrene-divinylbenzene) late> particles. Magnification 1200 x, (particle size = 16.0/rm average pore diameter = 200 nm).

Figure 16 Scanning electron micrograph of poly(cardanyl acrylate) beads.

The next two examples illustrate more complex surface reaction chemistry that brings about the covalent immobilization of bioactive species such as enzymes and catecholamines. Poly [bis (phenoxy)-phosphazene] (compound 1 ) can be used to coat particles of porous alumina with a high-surface-area film of the polymer (23). A scanning electron micrograph of the surface of a coated particle is shown in Fig. 3. The polymer surface is then nitrated and the arylnitro groups reduced to arylamino units. These then provided reactive sites for the immobilization of enzymes, as shown in Scheme III. 

FIGURE 3 Scanning electron micrograph (1200x magnification) of the surface of a porous alumina particle coated with poly(diphenoxy-phosphazene). Surface nitration, reduction, and glutaric dialdehyde coupling immobilized enzyme molecules to the surface. (From Ref. 23.)... 

Fig. 1.2 Scanning electron micrographs of (A) the silica wall of the diatom Stephcmopyxis turns (reproduced from [21] by permission ofWiley-VCH) and (B-D) singular morphologies of silica synthesized using poly-L-lysine and pre-hydro-lyzed tetramethyl orthosilicate (TMOS) under...

Figure 12. Scanning electron micrograph of negative images delineated in poly(TBMA-co-ST) resist at 7.6 mJ/cm2 of 254 nm radiation.

Fig. 10. Scanning electron micrographs of monolithic poly(divinylbenzene) capillary column. Note that the porous monolith is surrounded by an impervious tubular outer polymer layer resulting from copolymerization of the monomer with the acryloyl moieties bound to the capillary wall. This layer minimizes any direct contact of the analytes with the surface of the fused-silica capillary...

Figure 5. Transmission electron micrograph of poly[(CO,SA,TDI)-SIN-(S,DVB)], 10/90, after being fully polymerized and postcured. Oil phase is stained dark.

Introns in DNA can be visualized in an electron micrograph of DNA-mRNA hybrids (Figure 1-3-8). When mRNA hybridizes (base pairs) to the template strand of DNA, the introns appear as unhybridized loops in the DNA. The poly-A tail on the mRNA is also unhybridized, because it results from a posttranscriptional modification and is not encoded in the DNA. 

Figure 4 Electron micrographs of unchlorinated poly(vinyl acetate-co-oxazolidinone) (top) and chlorinated poly(vinyl acetate-co-oxazolidinone) (bottom) coated medical catheters exposed for 72 h to a flowing aqueous suspension of Pseudomonas aeruginosa (10 CFU/mL). 

Figure 7. High magnification scanning electron micrograph of decrosslinked and extracted cross-poly(n-butyl acrylate)-inter-cross-polystyrene IPN (80/20). The poly(n-butyl acrylate) phase was extracted. (Reproduced from Ref. 2 . Copyright 1982 American Chemical Society.)...

Fig. 6 Transmission electron micrograph (TEM) of the cross-section of a PDMAAm(poly-dimethylacrylamide)-b-PST(polystyrene) block-graft-copolymerized surface stained in iodine vapor, a Spurr s resin, b PST layer, c PDMAm layer, d dithiocarbamate (DC)-derivatized PST film...

Fig. 1.5.8 Scanning electron micrograph of poly(p-fer-butylstytene) particles obtained by polymerization of monomer droplets in the aerosol phase. The monomer and initiator flow rates were 1.2 dm3 min-1 and 40 cm5 min-1 and the boiler and initiator reservoir temperatures were 50°C and 25°C, respectively. The initiator was injected into the flowing aerosol at two positions. The modal diameter of these particles is 1.8 [xm. (From Ref. 67.)...

Fig. 12. Scanning electron micrograph (SEM) of poly(styrene/DVB) PolyHIPE...

The appearance of the individual microcapsules is shown in Fig. 1. Most individual microcapsules are approximately spherical and show a surface made up of deposited plates of poly(DL-lactic acid) in which the drug is embedded. Many of the larger microcapsules are cemented together by further plates of poly(DL-lactic acid). The effect of compression on these microcapsules is shown in Fig. 2. At a compressive force of 2 kN (Fig. 2(a)) the electron micrograph of the tablet fracture surface shows that the microcapsules, while distorted, remain essentially intact and rounded, with a relatively open porous structure to the tablet as a whole. At 10 kN force (Fig. 2(b)) the microcapsules at the fracture are flattened, cracked and distorted so that the fracture surface shows a far less open, porous aspect. Both of these microcap tablets have a very different appearance from that produced by the simple mixture (Fig. 3), where the individual plates of poly(DL-lactic acid) are mixed with the drug crystals in an open structure from which release would be easily... 

Fig. 2.63 Scanning electron micrograph showing a monolayer of pores in a PS-poly(para-phenylene) diblock copolymer film (Widawski et al. 1994). The scale bar represents 20//m.

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