Functional Thermal Printing

Conventionally, MlPs are obtained by bulk co-polymerization from a mixture consisting of a functional monomer, cross-linker, chiral template, and a porogenic solvent mixture. Nowadays, imprinting via non-covalent template binding is preferred over the covalent mode and involves three major steps (see Fig. 9.9). (i) Functional monomers (e.g. methacrylic acid, MAA) and a cross-linker (e.g. ethyleneglycol dimethacrylate, EDMA) assemble around the enantiomeric print molecule, e.g. (S)-phenylalanine anilide (1), driven by non-covalent intermolecular interactions, e.g. ionic interactions, hydrogen bonding, dipole-dipole interaction. Tr-rt-interaction. (ii) By thermally or photochemi-... 

In printed electronics, multiple functional layers are printed on top of each other. Each layer needs to be positioned in certain defined structures on top of the other. For example, a gate electrode in a FET needs to be positioned between the source and drain electrodes. If the gate electrode is mispositioned, the field-effect on the channel is not optimal anymore and device performance is reduced. This so-called registration requirement to the roll-to-roll printing process is much more stringent for printed electronics. Thermal post-treatment of a printed device may cause the substrate and all layers on it to shrink and may influence the registration as well, further complicating production. 

Adhesives used for screen or stencil printing in surface-mount applications are generally electrically insulative types whose functions are mechanical attachment and thermal dissipation. However, electrically conductive, silver-filled epoxies have been used for many years as ohmic contact adhesives to interconnect bare-chip devices in hybrid microcircuits and are used as solder replacements for surface mounting of components on printed-circuit boards. Regardless of their... 

In the covalent approach (Figure 2), a polymerizable derivative of the template is obtained by linking the template with a vinyl functional monomer via a strong reversible covalent bond (e.g., boronate esters, Schiff bases, or ketal). The derivatized print molecule is then radical copolymerized with an excess amount of a cross-linking agent, using either thermal or photochemical radical initiation. Reaction conditions are... 

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