Smart Materials

Thermochromic Inks Inks that change colour with temperature Useful on marketing materials Interesting gimmicks ! Has your egg been hot enough for long enough? A 2d temperature gauge

Polymorph Supplied as granules When heated to 62 degrees or above in water they form a pliable solid Useful for forming : handles/grips (developing ergonomics) Complex shapes Prototype patterns for casting or moulding Completing complex assemblies

Piezoelectric Materials 2 unique properties When deformed, they generate a small but measurable electrical current. When an electrical current is applied, they change size up to a 4% change in volume Applications Sensors The airbag sensors in cars detect force of impact Buzzers Low quality speakers

Shape Memory Alloys Made from any alloy of nickel/titanium At room temperature the spring is fully extended manually By heating up or applying a small electric current the spring will return to its original position and carry a load Possible applications Emergency shutter in case of fire of: Bin lids Blinds windows

Photochromic Materials Materials that change colour when exposed to light Possible Applications: energy-efficient windows that switch from transparent to opaque spontaneously upon exposure to increasing levels of sunlight. Reactions Lenses.

EPD (electronic paper displays) 1.Upper layer 2.Transparent electrode layer 3.Transparent micro- capsules 4.Positive charged white pigments 5.Negative charged black pigments 6.Transparent oil 7.Electrode pixel layer 8.Bottom supporting layer 9.Light 10.White 11.Black The three cells in the diagram represent the different states that each cell can be in. White state Grey state Black state Cross section

EPD (electronic paper displays) Key Features. Cells are stable so only use energy when changing state. Low energy consumption. Reflects light like paper rather than being “backlit” like an LCD display. Thin & flexible Multi cell addressing allows for a Hi-Def display. Recent advances can produce colour displays.

Liquid crystal displays (LCDs) Carbon based compounds that can show both liquid and solid crystal characteristics. When a cell containing a liquid crystal has a voltage applied, and light falls on it, it appears to go dark. This is caused by the molecular rearrangement within the liquid crystal. In the case of a digital clock or wristwatch, an LCD display has a pattern of conducting electrodes that can display numbers using a seven-segment display. The numbers are made to appear on the LCD by applying a voltage to certain segments, which go dark in contrast to the silvered background. As very small amounts of current are needed to power them, LCD displays are ideal for portable electronic devices such as mobile phones.

Liquid crystal displays (LCDs) The rapid advance of LCD technology led to the full colour LCD display commonly used in laptops. Here each pixel is divided up into three sub pixels with red, green or blue filters. By controlling and varying the voltage applied, the intensity of each sub pixel can create a range of over 256 colours. LCDs are now at the forefront of modern domestic appliance technology with even flatter, higher- resolution LCD televisions and computer screens. LCD displays: are thinner, so the TV, computer screen or laptop casing can be slimmer. This also means less material is used. have a higher resolution, leading to better picture quality than traditional cathode ray tube (CRT) TVs, which tended to flicker due to their lower resolution. use far less energy, saving both energy and costs. weigh less than CRTs, so they are more portable.

Transdermal prescription drug patches A transdermal patch is a medicated adhesive patch that delivers a specific dose of medication through the skin and into the bloodstream. The patch contains a drug reservoir sandwiched between a non- permeable back layer, and a permeable adhesive layer that attaches to the skin. The drug leaches slowly out of the reservoir, releasing small amounts of the drug at a constant rate for up to 24 hours. Advantages. Continuous controlled release. Painless. Discrete and can be applied with little fuss. Safe to use and dispose of. Less risk of overdose.

Transdermal prescription drug patches A major disadvantage is that the skin is a very effective barrier, so some prescription drugs, such as insulin for diabetes, cannot pass through the skin. Some prescription drugs can only be used in patches it they are combined with substances such as alcohol, to increase their ability to penetrate the skin. However, many prescription drugs can be delivered by transdermal patches, and they can be used to help people quit smoking, to relieve chronic pain and even as slimming aids.

Transdermal prescription drug patches