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Current Research Interests:
I. Adding Value and Functionality to
Traditional Textile Fibers via Tunable
Deposition of Polymers Nanolayers, Metal
Nanoparticles and Inorganic Materials
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a.) Controlling the permeability
of conventional textiles using
functional nanolayers of
polyelectrolytes
Image:
Transmission Electron Microscopy Image
of a cationic cotton fiber conformally
coated with 20 sequential nanolayers of
polystyrene sulfonate and
poly(Allyl amine Hydrochloride). The thickness and
composition of each layer controls the
transport of chemicals through the
modified textile without affecting its
comfort or mechanical properties.
Potential applications include
protective clothing for chemical and
biological warfare as well as moisture
control. |
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b.) Tunable Deposition of functional
nanoparticles for antibacterial and
structural coloration applications.
Image:
Transmission Electron Microscopy Image
of a cotton fiber coated with gold
nanoparticles. The nanoparticles are
assembled on the surface of the fiber by
controlling the electrostatic
interactions between the cationic cotton
and the anionic nanoparticles.
Potential applications include
catalytic mantles as well as platform
for biological sensors. Due to the high
surface coverage on the surface of the
fiber plasmonic effects are observed hence
creating coloration without the use of
dyes or pigments. |
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c.) Using Atomic
Layer Deposition for deposition of
inorganic materials for UV protection
applications.
Image:
Transmission Electron Microscopy Image
of a cotton fiber coated with layers of
aluminum oxide. Al2O3
layers were deposited using atomic layer
deposition procedures. Potential applications include
fabrics with inherent protection against
UV as well as catalytic flexible mantles. |
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II. Nanomanufacturing of
polymeric nanofibers using directed assembly
techniques as well as external fields
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a.) Position control of magnetic
nanoparticles inside polymeric
nanofibers for anticounterfeiting
applications
Image:
Transmission Electron Microscopy Image
of a polyethylene oxide nanofiber
embedded with magnetic nanoparticles.
The fiber was electrospun using a custom
made electrospinning setup that allows
the use of external fields to control
the direction of the flow as well as the
position of the nanoparticles inside the
nanofibers. Potential applications include
anti-counterfeting fibers as well supply
chain tracers of fabrics and fibrous
products. |
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b.) Antibacterial and catalytic
nanofibers for the decomposition of
hazardous gases and toxic industrial
chemicals
Image:
Field Emision Scanning Electron Microscopy Image
of nylon nanofibers conformally coated
with discrete silver nanoaparticles. A
large degree of nanoparticle dispersion
and coverage is achieved by judicious
manipulation of the chemical
interactions between the nanofibers and
the functional groups used to coat the
nanoparticles. Potential applications include
active filtration
against bacteria and viruses as well as
a platform for biological sensing. |
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III. Assessing Mechanical,
Electrical, Magnetic and Functional Properties
of Polymeric Materials Using Customized Scanning
Probe Microscopy Techniques
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a.) Probing electrical charge and
discharge of polymeric electrets via
Electrostatic
Force Microscopy
Image:
Electrical Field Gradient of a charged
polypropylene fiber obtained via
electrostatic force microscopy (EFM).
EFM is used to determine the magnitude
and location of electrical charges on
the electret fiber. Electret fibers are
commonly used in air respiration systems
and charge degradation of the polymer
electrets has been correlated to
decrease in filtration performance. |
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b.) Measuring the mechanical properties
of nanofibers and conjugated fibers
using
Acoustic
Force
Atomic Microscopy
Image:
Acoustic Force Atomic Microscopy Image
of a bicomponent polymeric fiber
(Islands on the sea configuration).
Acoustic force microscopy allows the
non-destructive measurement of the
mechanical properties of nanodomains
using the tip as a collector of sound
waves rather than as a poking device. |
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c.) Understanding lubrication and
friction phenomena at the nanoscale
using Lateral
Force Microscopy
techniques
Image:
Lateral Force Microscopy Image of a
cellulose substrate covered with a
lubricant commonly used in fiber
processing operations. Lateral
force microscopy measurements can
provide fundamental information on the
topography of the probed surface as well
as its frictional properties. LFM
measurements can also lead to the
development of intelligent criteria in
the formulation of lubricants by linking
lubrication performance to nanoscale
phenomena. |
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