Polyether polyamino methylene phosphonates (PAPEMP), a new type of reagent for water treatment, was synthesized from polyoxypropylene-diamine, phosphorous acid, formaldehyde and concentrated hydrochloric acid. The product was characterized by IR and NMR. The interactions between PAPEMP and calcite crystal were studied by means of simulated annealing molecular dynamics technique with period boundary condition. The essence of such interactions and scale inhibition mechanism of PAPEMP were also discussed tentatively. Results showed that the order of binding energies for PAPEMP (n＝1～8) with crystal surface of calcite was as follows: 5＞6＞4＞3＞8＞2＞7＞1, according to repeated units. The analysis on various interactions and pair correlation functions of all systems indicated that binding energies were mainly provided by coulomb interaction including electrovalent bond, and a little came from hydrogen bond, while van der Waals interaction was against the formation of combined systems on account of its positive value. From the energy analysis results, PAPEMP (n＝1～8) molecules could be conclusively deformed severely when they were combined with calcite crystal surface.

Key words: polyether polyamino methylene phosphonates, molecular dynamics, calcite, scale inhibition mechanism, binding energy, pair correlation function, deformation energy