Pressure Induced Topochemical Polymerizationof Solid Acryalmide Facilitated by Anisotropic Response of Hydrogen Bond Network

The pressure induced polymerization of molecular

solids is an appealing route to obtain pure,

crystalline polymers without the need for radical

initiators. Here, we report a detailed density

functional theory (DFT) based study of the

structural and chemical changes that occur in

defect free solid acrylamide, a hydrogen bonded

crystal, when it is subjected to hydrostatic pressures.

Our calculations predict a polymerization

pressure of 94 GPa, in contrast to experimental

estimates of 17 GPa, while being able

to reproduce the experimentally measured pressure

dependent spectroscopic features. Interestingly,

we find that the two-dimensional hydrogen

bond network templates a topochemical

polymerization by aligning the atoms through

an anisotropic response at low pressures. This

results not only in conventional C-C, but also

unusual C-O polymeric linkages, as well as a

new hydrogen bonded framework, with both NH...

O and C-H...O bonds.