Polymer Capture

Dissociative electron attachment is a radiation chemical reaction suitable for cutting a polymer just in half. If two equivalent polymer skeletons R are connected with a functional group XY that has a large cross section of dissociative electron attachment, the polymer captures an ejected electron at the center of the polymer skeleton and is broken into two fragments with similar molecular weight, as R-XY-R + e —>R-X + Y-R. The key to construct such a polymer is to find a functional group that is possible to connect two polymer chains, to capture an electron efficiently, and to dissociate into two fragments after the capture. 

The dangling bonds and polymer free radicals (on the surface of glow discharge treated polymer) capture molecular O2 or H2O, producing hydroxyl and carbonyl groups as schematically shown ... 

The polymers were synthesized by simply adding equal molar aqueous solutions of potassium tetrachloroplatinate 11 and the diamine-containing reactant with the resulting polymer captured as a precipitate. Polymer is formed in several minutes to several days depending on the reactivity of the Lewis base. The polymers can be made in gram to larger quantities as needed employing simple equipment and commercially available reactants. Thus, the polymers are ideally suited for commercialization. 

The utility of the general formulas is illustrated by treating a simple drift-diffusion process with a constant diffusion coefficient and a constant velocity. The limits of drift-domination and diffusion-domination, and the crossover behavior between these limits are discussed for various quantities of interest in the context of translocation. We shall use the key formulas provided here in later chapters dealing with polymer capture by a pore and polymer translocation through a pore. 

In addition to the above features of polymer capture, several novel behaviors of polymer molecules have been observed in translocation experiments. As an example, time-resolved fluorescence monitoring (Chen et al. 2004a) of labeled DNA molecules as they translocated through a solid-state nanopore of 15 nm in diameter showed that there is a very large capture region of radius 3 qm in front of the nanopore (Figure 9.2). Far from the pore, the molecules... 

We describe below some of the basic principles behind the physics of polymer capture. Our primary goal is to delineate different regimes for the... 

Figure 9.5 Polymer capture with convective diffusion.

Wong, C.T.A. and Muthukumar, M., 2007. Polymer capture by electroosmotic flow of oppositely charged nanopores, J. Chem. Phys., 126, 164903. 

With this goal in mind, this book strives to present a summary of the key concepts of polyelectrolyte structures, electrolyte solutions, ionic flow, mobility of charged macromolecules, polymer capture by pores, and threading of macromolecules through pores. The main concepts and theoretical results are presented without formal derivations whereas the cited references provide adequate derivations. For situations where there is a lack of readily usable references, derivations are given. Every effort has been made to give the reader... 

The mechanism of the encapsulation processes comprises mainly the formation and growth of the active component nuclei in the polymer-rich phase induced by mass transfer and phase transition, and the polymer capture/encapsulation of active component particles generated in an expanded solution droplet caused by the collision among these particles and polymer-rich phase. 

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