The impact of polymer architecture on network dynamics and self-healing was investigated using bottlebrushes containing side chains that were end-functionalized with 2-ureido-4[1H]-pyrimidinone (UPy). Bottlebrushes were synthesized using a graft-through approach utilizing ring-opening metathesis polymerization (ROMP) of poly(4-methylcaprolactone) macromonomers (P4MCL-OH) and P4MCL-UPy. Attaching UPy to the free end of bottlebrush side chains dilutes the impact of friction from complementary UPy interactions on segmental dynamics, leading to a much weaker dependence of the glass-transition temperature (Tg) on the molar fraction of UPy than observed in linear analogues, while the activation energy to dissociate UPy–UPy bonds (41–47 kJ/mol) remains mostly unchanged. Longer side chains result in a competition between reducing Tg and inducing entanglements that influence hydrogen-bonded network dynamics. Increasing the backbone length extends the sticky-Rouse region without affecting the network modulus (Gx) or UPy–UPy dissociation time (τs). Gx scales linearly with p and ranges from 27 kPa to 1.6 MPa, while τs remains nearly constant in contrast to linear telechelic ionomers, implying a similar self-healability across bottlebrush networks containing different amounts of UPy. These stretchable networks undergo almost perfect self-healing upon repeated rupture and melt pressing at ≤ 100 °C. Decorating bottlebrush polymers with hydrogen bonds creates opportunities to independently manipulate associative network dynamics and mechanical moduli.

Hydrogen bonding bottlebrush networks: self-healing materials from super-soft to stiff

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