A series of polyureas were synthesized through the reaction of aniline trimer with toluene-diisocyanate, diphenylmethane-4,4＇-diisocyanate, and hexamethylene-l,6-diisocyanate, respectively. The chemical structure of these polyureas was characterized and verified by FT-IR, ^1H NMR, elemental analysis, UV, XRD and CV. The conductivity of these polyureas ranged from 10^-7 to 10^-6 S/cm measured by four-point-probe instrument. Compared to the standalone aniline trimer, the stability （thermal stability and electrochemical stability）, response range and sensitivity of these polyureas are enhanced. The sensitivity of these polyureas DMF solution to pH value is superior to that of the standalone aniline trimer. The color of the polyureas DMF solution is greatly depended on pH value and the color change process is reversible, whenever from base to acid or from acid to base. These enhance- ments may give these polyureas more opportunities in order to be used as sensor materials.
Four kinds of poly（ethylene glycol） （PEG） derivatives with the similar backbone and different side groups have been synthesized successfully. When both catecholamine and double bond are tethered to polymer backbone, i.e., the PEG backbone, simultaneously, the polymer can accelerate the curing speed of ethyl a-cyanoacrylate （commer- cially available as 502） greatly under the same conditions （the curing time of such system is no more than 5 s）. Probably this is due to the autoxidation of catecholamines. Through the redox-cycling, catecholamines can produce, collect free radicals, and thus initiate the free radical polymerization. Due to the fast-curing of such material when mixed with a-cyanoacrylate, we could design and develop a new bicomponent super bioglue used in the dentistry or other bioenvironment requiring super fast settlement for further surgical operations.
