Nanotechnology and Design

Graphene Filters As explained in a previous post, graphene is a  graphene is an ultra-light yet immensely tough material that is 200 times stronger than steel. It is transparent as well as being the thinnest material possible and is an incredibly flexible conductor that can act as a perfect barrier which not even helium can pass through.   Scientists at the University of Manchester have developed a solution to one of our global problems with graphene: turning ocean water into potable drinkable H2O. Currently there are at least 1.2 billion people living in areas with insufficient potable water. This new discovery can quickly and easily turn one of our most abundant resources, seawater, into one of our most scarce — clean drinking water.   The new technique uses a new graphene-oxide membrane as a sieve that filters out salt molecules from water. The concept of using graphene-oxide membranes for desalinization isn’t new but this is the first successful a...

Neural Sensors This week in class we learned about different types of sensors. We also participated in a lab in which we made sensors that can detect the amount of sugar in a liquid. Delving deeper into such detectors, I looked at devices made out of biocompatible material that can be put into human bodies. Engineers at the University of California, Berkeley succeeded in creating the very first dust-sized wireless sensors that may be implanted within the body. These sensors do not require batteries. The device is powered through capturing the tiny amounts of energy that are emitted by smart phones and tablets, which use near-field communications (NFC). This is a type of technology that requires electromagnetic induction among antennae that are located inside portable devices.   The “neural dust” is implanted in the muscles and peripheral nerves of rats and is unique due to its use of ultrasound. Ultrasound vibrations are able to penetrate just about everywhere within t...

Hot Electrons and Photovoltaics The term hot electrons/carriers refer to electrons that have gained very high kinetic energy after being accelerated by a strong electric field in areas of high field intensities within a semiconductor device. Hot carriers can get stuck in unwanted areas of a device and cause degradation or instability.   Photovoltaics is the direct conversion of light into electricity at the atomic level. A typical photovoltaic system employs solar panels, each comprising a number of solar cells, which generate electrical power. However the efficiency of photovoltaic materials is compromised by their inability to capture all the energy absorbed when hot electrons form. Lead researcher Isabell Thomann of Rice University says “Hot electrons have the potential to drive very useful chemical reactions, but they decay very rapidly, and people have struggled to harness their energy.” In today’s best photovoltaic solar panels, most of the energy losses are the r...

Fluid Wettability This week we learned about the wettability of different surfaces. The experiment we had in class dealt with various ways we changed the exterior of a copper plate to make it into a super hydrophobic or super hydrophilic surface. While researching I came across an article that described a new material that switches from super hydrophobic to super hydrophilic in an instant. Copper was deposited onto a surface by a process called electrodeposition which makes it grow like an array of Christmas trees. Electrodeposition i.e. electroplating is a process that uses electric current to reduce dissolved metal cations so that they form a coherent metal coating on a conductive material. The scientists used copper because it is cheap and abundant but the team believes that the electrochemical manipulation of other metals, metal oxides, and mixed oxides may yield similar results.   They then ran a voltage through this new material and saw that water dropl...

Programmable Matter This week we had an experiment based on photolithography where we made circuit boards with this method. Photolithography is a process used to pattern parts of a thin film using light to transfer a geometric pattern from a photoresist onto the substrate. I decided to look further into lithography in general and was able to find a branch of nanotechnology concerning nanolithography. It’s the application of fabricating nanometer-scale structures with different approaches being optical, electron-beam, nanoimprint, multiphoton, scanning probe, and other lithography techniques.   All of these procedures are capable of producing patterns with at least one lateral dimension between 1 and 100 nm.   Researching this particular method led me to reading about programmable matter which is matter that has the ability to change its physical properties in a programmable fashion, based upon user input or autonomous sensing.   It seems, in t...

Nanotubes This week we learned about self-assembly which is a process where a disordered system spontaneously forms an organized structure. It is dependent on local interactions among components, without direct intervention.   I researched more into carbon nanotubes because they are exceptionally strong and lightweight yet they are created through self assembly. In addition, they have extraordinary thermal conductivity, mechanical, and electrical properties allowing them to find applications in various structural materials.   I delved more into the nanotubes’ electrical property and was able to find an article detailing findings on a carbon nanotube yarn that converts mechanical energy into electrical energy. Scientists tangled carbon nanotubes into yarn which was then submerged into an electrolyte gel that was able to generate a small current of electricity when tensile or torsional motion was applied to it. They called these Twistron yarn.  A s...