Polymer alloys are usually classified
into polymer blends and block copolymers. Herein, we combine the two
alloying strategies to endow materials with a thermoinduced sol–gel
transition. Our system is composed of two amphiphilic block copolymers
in water, and we suggest terming it a “block blend.”
A series of “computer experiments” by dynamic Monte
Carlo simulations were carried out to verify our idea of “block
blends” and revealed the mechanism of the underlying physical
gelation. A thermogel was achieved after blending two amphiphilic
block copolymers with different lengths of hydrophobic and hydrophilic
blocks and thus different extents of the hydrophilicity–hydrophobicity
balances, in which one copolymer could otherwise always flow and the
other could be insoluble in water prior to the blending. It is thus
interesting that “block blends” can make non-thermogellable
copolymers useful in thermogellable systems. We also examined “averaged”
copolymers which shared the same composition with the block blends,
and our comparative studies illustrated that the block blends impregnated
richer physics. A thermogel has a percolated micelle network. Although
the amphiphilicity of the copolymer determines the micelle formation,
the spatial heterogeneity of two copolymers is crucial in further
formation of the network, where semibald micelles are connected by
hydrophobic channels rich in the relatively more hydrophobic copolymer.
The block-blend strategy paves a way to generate an intelligent material,
in particular, a biomaterial by hierarchical self-assembly.