Civil Engineering Reference
In-Depth Information
Figure 12.8
Field emission scanning electron microscope images of (a) cellulose-only i bers,
(b) cellulose-heparin composite i bers. (Adapted from Reference [99]).
heparin in an electrospun cellulose i ber acted as an anticoagulant slowing clot forma-
tion without altering the i nal amount of clot formed. It was also observed that heparin
maintained its bioactivity even at er an exposure to high voltages (10-20 kV) required
in the electrospinning process and the method of preparation of cellulose/heparin com-
posite i bers of er promise in the formation of woven fabrics for use in the construction
of artii cial vessels with excellent blood compatibility.
Composite of electrospun nanoi bers of natural cotton cellulose were prepared the
hydrothermal method [75]. Composite is prepared by using the as prepared cellu-
lose i ber by electrospinning as the template and the i bers were functionalized with
a rare-earth nano-oxide material of cerium dioxide (CeO
2
). h e nanoi ber mats were
immersed in the transparent precursor solution of cerium dioxide and heat treated at
high temperature. h e morphology of resulted composite mats showed that hydro-
thermally grown CeO
2
nanoparticles exhibited a polycrystalline cubic l uorite struc-
ture and could be dispersed uniformly on the surface of the cellulose nanoi ber. h ere
were rarely adhesions or aggregations at the intersection of the electrospun i bers were
observed. h e uniformity in dispersion of the nanoparticles greatly depends on the
hydrothermal processing time. h e small CeO
2
nanoparticles of size 40-60 nm dis-
persed greatly on the surface of the natural cellulose nanoi bers at a hydrothermal
processing time of 3 h, while the particles size increased with increasing processing
time with the elongation of the reaction time to 6 h, the CeO
2
nanoparticles grew up
to about 100-120 nm.
CeO
2
nanoparticles were attached to the surface of the nanoi ber substrate due
to the strong interfacial and electrostatic interactions between the carboxylic or
hydroxyl groups of the cellulose nanoi ber and the CeO
2
nanoparticles, which is
ef ectively prevented nanoparticle fall-of . Compared to the natural cotton cellulose
nanoi bers, the modii ed natural cotton cellulose nanoi bers by hydrothermal incor-
poration of CeO
2
nanoparticles showed excellent protection against UV radiation
because of the function of the CeO
2
particles. h is functional nanoi ber will have
potential applications in various areas, such as the medical, military, biological, and
optoelectronic industrial i elds including UV protection for data storage or memory
devices, in the future.
