Nanofibers
composed of silica nanoparticles, used as structural
building blocks, and polystyrene nanoparticles introduced as sacrificial
material are fabricated by bicolloidal electrospinning. During fiber
calcination, sacrificial particles are combusted leaving voids with
controlled average sizes. The mechanical properties of the sintered
silica fibers with voids are investigated by suspending the nanofiber
over a gap and performing three-point bending experiments with atomic
force microscopy. We investigate three different cases: fibers without
voids and with 60 or 260 nm voids. For each case, we study how the
introduction of the voids can be used to control the mechanical stiffness
and fracture properties of the fibers. Fibers with no voids break
in their majority at a single fracture point (70% of cases), segmenting
the fiber into two pieces, while the remaining cases (30%) fracture
at multiple points, leaving a gap in the suspended fiber. On the other
hand, fibers with 60 nm voids fracture in only 25% of the cases at
a single point, breaking predominantly at multiple points (75%). Finally,
fibers with 260 nm voids fracture roughly in equal proportions leaving
two and multiple pieces (46% vs 54%, respectively). The present study
is a prerequisite for processes involving the controlled sectioning
of nanofibers to yield anisometric particles