What's my model for polymers? Probably similar to yours, but I keep tacking on new aspects over time. Everyone has the long chain. Without that, you're not a polymer person - it's that simple. Go long or don't go at all.
But here's some of my additions and why they are there. First, the chain is always moving. Whether from Brownian motion or stress relaxation, it's always on the go. Even with an end (or two!) tethered to a surface, it's wriggling like an earthworm. Or maybe the snake pit that Indiana Jones despised so much.Even in solids, you still have localized motions of the crankshaft type, all of which are needed to explain diffusion of water or oxygen through packaging materials. These additions were added when I started studying rheology.
Another addition are defects. These are a little harder to imagine in great details because the nature of it varies greatly from one polymer to another. Some examples
- chain ends and the gaps they create
- improperly incorporated monomer in the chain (such as head-to-head addition instead of head-to-tail)
- incorporation of the catalyst, initiators, ...
- crystal defects, and
- tie molecules in semi-crystalline polymers
I'm sure there are other additions, but they are comparatively minor. Please feel free to suggest what you carry around, as new additions can be good.