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Nazmul Karim

Publications and source records attributed to Nazmul Karim.

21 records · Page 2Linked to original sources

Graphene-enabled adaptive infrared textiles

Interactive clothing requires sensing and display functionalities to be embedded on textiles. Despite the significant progress of electronic textiles, the integration of optoelectronic materials on fabrics still remains as an outstanding challenge. Here, using the electro-optical tunability of graphene, we report adaptive optical textiles with electrically controlled reflectivity and emissivity covering the infrared and near-infrared wavelengths. We achieve electro-optical modulation by reversible intercalation of ions into graphene layers laminated on fabrics. We demonstrate a new class of infrared textile devices including display, yarn and stretchable devices using natural and synthetic textiles. To show the promise of our approach, we fabricated an active device directly onto a t-shirt which enables long-wavelength infrared communication via modulation of the thermal radiation from the human body. The results presented here, provide complementary technologies which could leverage the ubiquitous use of functional textiles.

physics.app-ph↗

Ultra-High Performance of Nano-Engineered Graphene-Based Natural Jute Fiber Composites

Natural fibers composites are considered as sustainable alternative to synthetic composites due to their environmental and economic benefits. However, they suffer from poor mechanical and interfacial properties due to a random fiber orientation and weak fiber-matrix interface. Here we report nano-engineered graphene-based natural jute fiber preforms with a new fiber architecture (NFA) which significantly improves their properties and performances. Our graphene-based NFA of jute fiber perform enhances Young modulus of jute-epoxy composites by ~324% and tensile strength by ~110% more than untreated jute fiber composites, by arranging fibers in parallel direction through individualisation and nano surface engineering with graphene derivatives. This could potentially lead to manufacturing of high performance natural alternatives to synthetic composites in various stiffness driven high performance applications.

physics.app-ph↗

All Inkjet-Printed Graphene-Silver Composite Inks for Highly Conductive Wearable E-Textiles Applications

Inkjet-printed wearable electronic textiles (e-textiles) are considered to be very promising due to excellent processing and environmental benefits offered by digital fabrication technique. Inkjet-printing of conductive metallic inks such as silver (Ag) nanoparticles (NPs) are well-established and that of graphene-based inks is of great interest due to multi-functional properties of graphene-based materials. However, poor ink stability at higher graphene concentration and the cost associated with the higher Ag loading in metal inks have limited their wider use. Moreover, graphene-based e-textiles reported so far are mainly based on graphene derivatives such as graphene oxide (GO) or reduced graphene oxide (rGO), which suffers from poor electrical conductivity. Here we report inkjet printing of highly conductive and cost-effective graphene/Ag composite inks for wearable e-textiles applications. The composite inks were formulated, characterised and inkjet-printed onto PEL paper first and then sintered at 150 C for 1 hr. The sheet resistance of the printed patterns is found to be in the range of ~0.08 - 4.74 ohm/sq depending on the number of print layers and the graphene/Ag ratio in the formulation. The optimised composite ink was then successfully printed onto surface pre-treated (by inkjet printing) cotton fabrics in order to produce all-inkjet-printed highly conductive and cost-effective electronic textiles.

physics.app-ph↗