A proton-exchange membrane, or polymer-electrolyte membrane (PEM), is a semipermeable membrane generally made from ionomers and designed to conduct protons while acting as an electronic insulator and reactant barrier, e.g. to oxygen and hydrogen gas. This is their essential function when incorporated into a membrane electrode assembly (MEA) of a proton-exchange membrane fuel cell or of a proton-exchange membrane electrolyser: separation of reactants and transport of protons while blocking a direct electronic pathway through the membrane. PEMs can be made from either pure polymer membranes or from composite membranes, where other materials are embedded in a polymer matrix. One of the most common and commercially available PEM materials is the fluoropolymer (PFSA) Nafion, a DuPont product. While Nafion is an ionomer with a perfluorinated backbone like Teflon, there are many other structural motifs used to make ionomers for proton-exchange membranes. Many use polyaromatic polymers, while others use partially fluorinated polymers. Proton-exchange membranes are primarily characterized by proton conductivity (σ), methanol permeability (P), and thermal stability. PEM fuel cells use a solid polymer membrane (a thin plastic film) which is permeable to protons when it is saturated with water, but it does not conduct electrons. (Wikipedia).
Structure Of The Mitochondria | A level & IB Biology | Science with Hazel
With Hazel unable to record at the moment, Martin takes you through the structure and function of the mitochondria. Each mitochondrion has a double membrane. The outer membrane contains transport proteins to shuttle pyruvate into the matrix, and the inner membrane contains electron transp
From playlist A Level & IB Biology //
In an ionic bond, two ions are held together by electrostatic force. These two atoms are trying to attain full valence shells of eight electrons. One atom has too many electrons and another has too few so one atom donates electrons and the other accepts them. The donor atom forms a cation,
From playlist Chemistry
Structure Of The Cell Membrane: Active and Passive Transport
What is it that separates what's inside a cell from what's outside of a cell? Why, that's the cell membrane. What's it made out of? How does it work? How do molecules get in and out of the cell? These are super-important concepts! Let's take a look. Watch the whole Biochemistry playlist:
From playlist Biochemistry
Ionic and Covalent Bonding - Chemistry
This chemistry video tutorial provides a basic introduction into ionic and covalent bonding. It explains the difference between polar covalent bonds and nonpolar covalent bonds. Ionic bonds exist between metals and nonmetals and are made up of ions with positive and negative charges. Co
From playlist New AP & General Chemistry Video Playlist
LHCNews Nov 12, 2009 - Protons are back in the LHC!
After more than a year, protons were injected into the LHC...
From playlist The Large Hadron Collider
IONIC BOND - a quick definition
A quick definition of an ionic bond. Chem Fairy: Louise McCartney Director: Michael Harrison Written and Produced by Kimberly Hatch Harrison ♦♦♦♦♦♦♦♦♦♦ Ways to support our channel: ► Join our Patreon : https://www.patreon.com/socratica ► Make a one-time PayPal donation: https://www.p
From playlist Chemistry glossary
26. Oxidative Phosphorylation/Photosynthesis I
MIT 7.05 General Biochemistry, Spring 2020 Instructor: Matthew Vander Heiden View the complete course: https://ocw.mit.edu/7-05S20 YouTube Playlist: https://www.youtube.com/playlist?list=PLUl4u3cNGP62wNcIMfinU64CAfreShjpt Professor Vander Heiden continues the discussion of topics related
From playlist (Selected Lectures) MIT 7.05 General Biochemistry, Spring 2020
Uniporters, symporters and antiporters | Biology | Khan Academy
A review of various forms of passive and active transport including facilitated diffusion (uniporters), symporters, and exchangers; a discussion of primary and secondary active transport. Watch the next lesson: https://www.khanacademy.org/science/biology/membranes-and-transport/bulk-trans
From playlist Membranes and transport | Biology | Khan Academy
MIT 7.05 General Biochemistry, Spring 2020 Instructor: Matthew Vander Heiden View the complete course: https://ocw.mit.edu/7-05S20 YouTube Playlist: https://www.youtube.com/playlist?list=PLUl4u3cNGP62wNcIMfinU64CAfreShjpt In this lecture, Professor Vander Heiden introduces oxidative phosp
From playlist (Selected Lectures) MIT 7.05 General Biochemistry, Spring 2020
Lec 2 | MIT 7.012 Introduction to Biology, Fall 2004
Biochemistry 1 (Prof. Robert A. Weinberg) View the complete course: http://ocw.mit.edu/7-012F04 License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu
From playlist MIT 7.012 Introduction to Biology, Fall 2004
Can You Believe It? #19 The Structure of a Proton
Visit http://ilectureonline.com for more math and science lectures! To donate: http://www.ilectureonline.com/donate https://www.patreon.com/user?u=3236071 We will learn the intricate structure of a proton at the level of the gluon and quarks. Previous video in this series can be seen at
From playlist CAN YOU BELIEVE IT?
Mod-12 Lec-28 Solid Oxide Fuel Cell
Advanced ceramics for strategic applications by Prof. H.S. Maiti,Department of Metallurgy and Material Science,IIT Kharagpur.For more details on NPTEL visit http://nptel.ac.in
From playlist IIT Kharagpur: Advanced Ceramics for Strategic Applications | CosmoLearning.org Materials Science
Chemistry Essentials: What's the atomic number of an element?
A quick definition of the atomic number of an element. Chem Fairy: Louise McCartney Director: Michael Harrison Written and Produced by Kimberly Hatch Harrison ♦♦♦♦♦♦♦♦♦♦ Ways to support our channel: ► Join our Patreon : https://www.patreon.com/socratica ► Make a one-time PayPal donati
From playlist Chemistry glossary
27. Photosynthesis II/CO2 Assimilation
MIT 7.05 General Biochemistry, Spring 2020 Instructor: Matthew Vander Heiden View the complete course: https://ocw.mit.edu/7-05S20 YouTube Playlist: https://www.youtube.com/playlist?list=PLUl4u3cNGP62wNcIMfinU64CAfreShjpt Professor Vander Heiden discusses light reactions versus dark react
From playlist (Selected Lectures) MIT 7.05 General Biochemistry, Spring 2020
Lec 5 | MIT 7.012 Introduction to Biology, Fall 2004
Biochemistry 4 (Prof. Robert A. Weinberg) View the complete course: http://ocw.mit.edu/7-012F04 License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu
From playlist MIT 7.012 Introduction to Biology, Fall 2004
MIT 5.08J Biological Chemistry II, Spring 2016 Instructor: JoAnne Stubbe View the complete course: https://ocw.mit.edu/5-08JS16 YouTube Playlist: https://www.youtube.com/playlist?list=PLUl4u3cNGP63vvR4xtexZdoPywRYIZI0- This metal homeostasis lecture will delve into iron metabolism. Profe
From playlist MIT 5.08J Biological Chemistry II, Spring 2016
Introduction to Chemical Biology 128. Lecture 15. Glycobiology & Polyketides.
UCI Chem 128 Introduction to Chemical Biology (Winter 2013) Lec 15. Introduction to Chemical Biology -- Glycobiology & Polyketides -- Part 1 View the complete course: http://ocw.uci.edu/courses/chem_128_introduction_to_chemical_biology.html Instructor: Gregory Weiss, Ph.D. License: Creati
From playlist Chem 128: Intro to Chem Biology
2020 Solar Fuels Science Meeting: Solar Fuels - Future Science and Technology
©2020 California Institute of Technology
From playlist Sustainability
Electron Transport Chain - ATP Synthase, Chemiosmosis, & Oxidative Phosphorylation
This biology video tutorial provides a basic introduction into the electron transport chain - a series of membrane bound proteins that shuttle the electrons from NADH to an electron acceptor such as Oxygen. ATP synthase is the enzyme responsible for producing ATP using the energy extracte
From playlist Biochemistry