Entropy is usually about things falling apart, but it can actually act like a glue that pulls tiny fibers together.
March 13, 2026
Original Paper
Scaling Laws and Paradoxical Metastable States in Nanofilament Entropic Separation
arXiv · 2603.11732
The Takeaway
We are taught that entropy makes things messy and spread out, but at the nanoscale, a 'paradoxical' regime exists where the movement of particles forces nanofibers into tight bundles. This challenges the common view that entropic forces only drive systems toward disaggregation.
From the abstract
Entropic forces play a fundamental role in nanoscale phenomena, from colloidal self-assembly to biomolecular disaggregation. Here, we develop an exact analytical theory and find general scaling laws for the entropic separation of tether-mediated nanofilament bundles, revealing that a single dimensionless parameter--the ratio of the excluded-volume radius to the tether length--dictates whether filaments are pushed apart or, contrary to the usual expectation, pulled together. This unexpected regim