I know one easy method to make a data file for a polymer with pcff force field. This method is building the structure in Materials Studio, then assigning the pcff/cvff/compass force field using Discover Module. Finally using msi2lmp.exe we can make the data file for lammps.
However, for those who do not have access to Materials Studio and Discover Module, how can they assign the pcff force filed to the built polymer structure and make the corresponding data file? What are the alternative procedures for this job?
Try using Xenoview (I think it is free). I haven’t used it but have heard about it. It has a builder and some published force-field parameters. You can import your molecule there and assign PCFF force field (basically atomtypes) and save in mdf car format. Probably worth a shot.