Construction of electronic cigarettes
Engineering and chemistry of e-cigarettes / From Wikipedia, the free encyclopedia
An electronic cigarette is a handheld battery-powered vaporizer that simulates smoking, but without tobacco combustion.[1] E-cigarette components include a mouthpiece (drip tip[2]), a cartridge (liquid storage area), a heating element/atomizer, a microprocessor, a battery, and some of them have an LED light on the end.[3] An atomizer consists of a small heating element, or coil, that vaporizes e-liquid and a wicking material that draws liquid onto the coil.[4] When the user inhales a flow sensor activates the heating element that atomizes the liquid solution;[5] most devices are manually activated by a push-button.[6] The e-liquid reaches a temperature of roughly 100–250 °C (212–482 °F) within a chamber to create an aerosolized vapor.[7] The user inhales an aerosol, which is commonly but inaccurately called vapor, rather than cigarette smoke.[8] Vaping is different from smoking, but there are some similarities, including the hand-to-mouth action of smoking and an aerosol that looks like cigarette smoke.[1] The aerosol provides a flavor and feel similar to tobacco smoking.[1] There is a learning curve to use e-cigarettes properly.[9] E-cigarettes are cigarette-shaped,[10] and there are many other variations.[11] E-cigarettes that resemble pens or USB memory sticks are also sold that may be used unobtrusively.[12]
There are three main types of e-cigarettes: cigalikes, looking like cigarettes; eGos, bigger than cigalikes with refillable liquid tanks; and mods, assembled from basic parts or by altering existing products.[13] Cigalikes are either disposable or come with rechargeable batteries and replaceable nicotine cartridges.[14] A cigalike e-cigarette contains a cartomizer, which is connected to a battery.[15] A "cartomizer" (a portmanteau of cartridge and atomizer[16]) or "carto" consists of an atomizer surrounded by a liquid-soaked poly-foam that acts as an e-liquid holder.[4] Clearomizers or "clearos", not unlike cartotanks, use a clear tank in which an atomizer is inserted.[17] A rebuildable atomizer or an RBA is an atomizer that allows users to assemble or "build" the wick and coil themselves instead of replacing them with off-the-shelf atomizer "heads".[18] The power source is the biggest component of an e-cigarette,[19] which is frequently a rechargeable lithium-ion battery.[11]
As the e-cigarette industry continues to evolve, new products are quickly developed and brought to market.[20] First-generation e-cigarettes tend to look like traditional cigarettes and so are called "cigalikes".[18] Most cigalikes look like cigarettes but there is some variation in size.[15] Second-generation devices are larger overall and look less like traditional cigarettes.[21] Third-generation devices include mechanical mods and variable voltage devices.[18] The fourth-generation includes sub ohm tanks and temperature control devices.[22] The voltage for first-generation e-cigarettes is about 3.7[23] and second-generation e-cigarettes can be adjusted from 3 V to 6 V,[24] while more recent devices can go up to 8 V.[23] The latest generation of e-cigarettes are pod mods,[25] which provide higher levels of nicotine than regular e-cigarettes[26] through the production of aerosolized protonated nicotine.[27]
E-liquid is the mixture used in vapor products such as e-cigarettes[28] and usually contain propylene glycol, glycerin, nicotine, flavorings, additives, and differing amounts of contaminants.[29] E-liquid formulations greatly vary due to fast growth and changes in manufacturing designs of e-cigarettes.[15] The composition of the e-liquid for additives such as nicotine and flavors vary across and within brands.[30] The liquid typically consists of a combined total of 95% propylene glycol and glycerin, and the remaining 5% being flavorings, nicotine, and other additives.[31] There are e-liquids sold without propylene glycol,[32] nicotine,[33] or flavors.[34] The flavorings may be natural, artificial,[30] or organic.[35] Over 80 chemicals such as formaldehyde and metallic nanoparticles have been found in the e-liquid.[36] There are many e-liquids manufacturers in the US and worldwide,[37] and more than 15,500 flavors existed in 2018.[38] Under the US Food and Drug Administration (FDA) rules, e-liquid manufacturers are required to comply with a number of manufacturing standards.[39] The revision to the EU Tobacco Products Directive has some standards for e-liquids.[40] Industry standards have been created and published by the American E-liquid Manufacturing Standards Association (AEMSA).[41]