Poly replication method

Donor-acceptor interaction between monomer and polymer template offers an elegant methods of replication degree of polymerization. Similar system was described for copolymerization of vinylpyridine with p-chlorostyrene in the presence of poly(maleic anhydride) used as template. " ... 

An alternative method is to use mixtures of concentrated sulfuric acid and potassium permanganate, giving contrast between crystals and amorphous domain that turns out to be applicable to many different polymers, e.g. polyethylene, polypropylene, poly(but-l-ene), polystyrene and poly(aryl ether ketone)s. The strong etchant degrades the amorphous phase more quickly than the crystals and the resulting topography is revealed by heavy metal shadowing. Replicates are prepared which are examined in the electron microscope. 

The removal of direct carbon replicas is dependent upon the polymer. Boiling xylene vapor was used to remove drawn PE from replicas [296] in work on drawn polymer morphology. Hobbs and Pratt [297] described a direct carbon replica method for replication of a PBT impact fracture surface by evaporation of platinum at 20° and PBT removal in hexafluor-oisopropanol (HFIP). Latex film coalescence in poly(vinyl acrylate) homopolymer and vinyl acrylic copolymer latexes was studied using direct replicas [298]. As the latex films have a low glass transition temperature, they were cooled by liquid nitrogen to about -150°C in the vacuum evaporator and shadowed with Pt/ Pd at 45° followed by deposition of a carbon support film at 90° to the specimen surface. The latex films were dissolved in methyl acetate/ methanol. TEM micrographs of the latex films show the difference between films aged for various times (Section 5.5.2). 

Various methods have been presented in the literature to fabricate microfluidic devices. One of the most widely used are those made from poly(dimethylsiloxane) (PDMS) gels [8,10]. The materials for these devices are relatively inexpensive and they can be made with established soft lithography processes. This approach also has the potential to form complicated and intricate flow patterns. The soft lithography process is robust and reproducible, which allows replicating flows in different devices that have the same design. 

---