# Near melting thermoplastic material accumulates in the sharper corners. What is this phenomenon?

I have a part made of a thermoplastic material. When I heat it up and cool it down, the dimension of the part changes non-uniformly. Somehow the melted material tries to fill the sharper corners. So for example if there is a corner with a fillet of $r_1$ and wall thickness of $t_1$, after a high temperature experiment the part deforms to $r_2$ and $t_2$ where

$$\left(t_2-t_1\right)<\left(r_1-r_2\right)$$

I know it has to do with adhesion and capillary, but not knowing that much about chemistry jargon, I'm not able to find the right term for this phenomena. I would appreciate if you could help me know if this phenomena has a name and what parameters control this behaviour?

• It can be probably explained as a tip effect in term of chemical potential. I think. Dec 11 '17 at 9:19
• I think it is just capillary pressure, as simple as that. Dec 11 '17 at 9:28
• Some things in this direction: chem.atmos.colostate.edu/AT620/Sonia_uploads/… Dec 11 '17 at 9:28
• @Foad Sorry, I read your question again and realized what I suggested is irrelevant here. One can delete own comments within 5 min:) I agree with Ivan and what you suggested in the question: capillary effect, it's just that simple. Dec 11 '17 at 9:32
• @andselisk One can delete own comments until forever. 5 min is just the limit for edits. Dec 11 '17 at 9:42