Materials You Know Ceramics (inorganic, nonmetallic solids)

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1 Moder Materials ad PSU esearch irst school to offer a materials curriculum i Developed the first iterdiscipliary materials laboratory i Pe State is raked #1 i the US i expeditures for materials research, $50,000,000 Pe State s Materials esearch Istitute (MI) is oe of the Materials Sciece ad Egieerig eters fuded by NS (MSE, iterdiscipliary research groups workig o:! Biomolecular / Biomimetic Materials! odesed Matter Pheomea! Eergy / Sustaiability! Mechaics of Materials! Multiferroics / Magetics / Spitroics! Naostructures / Naoparticles! Polymers! Semicoductors / Photoics / rgaic Electroics! Soft Materials / olloids 200+ faculty members, 100 esearchers, ad 800 Graduate Studets are associated with MI. 15 Academic departmets, 5 colleges 21 research ceters housed at Pe State are curretly workig o materials research icludig: eter for Naoscale Sciece Particulate Materials eter arbo esearch eter eter for Dielectric Studies EM 112 LSVDS Materials 1 Materials You Kow eramics (iorgaic, ometallic solids) Material: Zeolites for water softeig. Differet amouts of zeolites i detergets depedig o geographic locatio. Sodium Zeolite A Polymers Material: Kevlar for bullet proof vests. Polymer structure produces strog itermolecular forces for a strog material. Kevlar EM 112 LSVDS Materials 2

2 Polymers eview rgaic hemistry The chemistry of compouds cotaiig boded to.!also may cotai, N, S, ad haloges easos for large umbers of orgaic compouds: 1.! arbo atoms ca form strog, stable bods to other atoms (small size) 2.! arbo atoms form up to 4 bods simultaeously: (valece of 4) 3.! arbo atoms ca form multiple bods (Small size ad valece of 4) 4.! The - bod is opolar, but bods to other elemets are polar (N,, haloges). (electroegativity) EM 112 LSVDS Materials 3 lasses of rgaic ompouds lassificatio is ecessary to maage the large umber of compouds lasses of YDABNS: otai oly ad (Simplest orgaic compouds) 1) alkaes all sigle bods 2) alkees oe or more double bods 3) alkyes oe or more triple bods 4) aromatic alteratig sigle ad double bods i a rig EM 112 LSVDS Materials bezee 4

3 Additio eactios - Double ad triple bods are reactive: additio reactios typically occur at room temperature. or Alkees 3 #= 2 + Br 2 $ Br Br 3 #=# 3 + X $ where X = l, Br, I,, etc. X or Alkyes 3 #% + 2 Br 2 $ Br Br Br Br 3 - % l $ l l EM 112 LSVDS Materials 5 uctioal Group lasses otai a represetative group of elemets i a fixed patter: Each class has similarities i structure ad fuctio (reactivity),, = alkyl group Alcohols - " Ethers -- ad " Amies N N ' N ' " uctioal Groups which cotai a carboyl group ' Aldehydes Ketoe ( ad ") ' N' arboxylic Acid Ester Amide EM 112 LSVDS Materials 6

4 odesatio eactios Two molecules joi by elimiatig a small molecule (such as water) Ethers, Esters, ad Amides are formed via codesatio reactios: alcohol + alcohol #$ ether + water ## + ## #$ ## + 2 carboxylic + alcohol $ ester + water acid + ## $ ' + 2 carboxylic + amie $ amide + water acid N + $ + 2 N' EM 112 LSVDS Materials 7 igh molecular weight materials formed from may small molecules called moomers Moomer = repeatig uit What Materials do you kow are Polymers? PLYMES Polymer Sythesis 1.! Additio polymers Moomer cotais a double bod; polymers form via additio reactios Examples: ubber, ross-likig of PVA 2.! ig opeig yclic moomer opes to form a liear chai (such as the polymerizatio of Sulfur) 3.! odesatio polymers polymers form via codesatio reactios a small molecule ( 2, l, 2 ) is elimiated i the reactio Example: Silicoe polymers EM 112 LSVDS Materials 8

5 Double bod opes up, two electros are used to form two ew - sigle bods coectig moomers Styrofoam (Polystyree) Additio Polymer 2 EM 112 LSVDS Materials 9 ethylee 2 2 polyethylee(gladwrap) tetrafluoroethylee 2 2 Teflo,Tal 2 stryree l viyl chloride polystyree(styrofoam) 2 l polyviyl chloride(pv) methyl methacrylate MMA 3 polymma (Plexiglass) EM 112 LSVDS Materials 10

6 ubber: A aturally occurrig Additio Polymer EM 112 LSVDS Materials 11 ig peig Polymerizatio yclic moomer opes to form a liear chai odesatio Polymerizatio Two molecules joi to form a larger molecule by elimiatio of a small molecule such as water Polyurethae N N ' Used i: foam furiture stuffig spray-o isulatio auto parts water-protective coatigs EM 112 LSVDS Materials 12

7 odesatio Polymers ( 2 ) 4 + N ( 2 ) 6 N ( 2 ) 4 N ( 2 ) 6 N Nylo 6,6 (polyamide) EM 112 LSVDS Materials 13 Properties of polymers Polymers form glasses Above T m : polymer is liquid-like (fluid chais) Below T m : wats to crystallize, but ca t Betwee T m ad T g = elastomer T g = glass trasitio temperature: substace becomes amorphous solid (glass) Elastomer turs to a brittle solid EM 112 LSVDS Materials 14

8 Properties deped o: 1)! Degree of rystalliity; how does it pack together?!!!!!! 2)! Iteractios betwee chais; cross-likig!!!! Properties of Polymers EM 112 LSVDS Materials 15 Degree of crystalliity: amout of orderig i a polymer Polymer chais ted to be flexible ad easily etagled or folded; ted to be disordered! hard to crystallize; ofte amorphous rystalliity affects optical properties: 1) Amorphous polymers are trasparet (glasslike) 2)! Polymers that are partly crystallie ad partly glassy are traslucet rystalliity affects physical properties: crystallie polymers are stiffer, harder, more dese EM 112 LSVDS Materials 16

9 Icreasig order i a polymer Iteractios betwee chais of a polymer led elemets of order to the structure of polymers. Stretchig (or extrudig) the polymer chais as they form ca icrease the amout of order, leadig to a greater degree of crystalliity i the polymer. EM 112 LSVDS Materials 17 actors that affect rystalliity 1) Side chais ca affect packig ad crystalliity: Isotactic packs well; is more crystallie. Plastics will be stiffer: used to make tupperware Atactic is amorphous: Does t pack well: used to make flexible plastics (garbage bags) 2) Average molecular mass affects degree of crystalliity: compare low ad high desity polyethylee LDPE: average molecular mass of 10 4 amu DPE: average molecular mass of 10 6 amu EM 112 LSVDS Materials 18

10 Iteractios betwee chais rosslikig: covalet bods betwee chais: icreases stiffess, stregth. Examples: rubber, PVA, Silicoe Metal ios ca serve as cross-likig agets Example: Sodium algiate Itermolecular forces ca hold polymer chais together: a) LD s hold chais i opolar polymers together: Polyethylee, polypropylee b) dipole-dipole c) ydroge-bodig plays a importat role i biological polymers DNA, Proteis EM 112 LSVDS Materials 19 Vulcaizatio of ubber Bods formed betwee chais make the polymer stiffer; more crystallie Natural rubber is too soft ad chemically reactive to make a useful material. By vulcaizig the rubber (crosslikig the chais with sulfur) useful materials are made. 3 S heat Isopree (moomer) Natural rubber (gummy) ross-liked rubber (tough elastomer) EM 112 LSVDS Materials 20

11 = viyl alcohol rosslikig Poly(viylalcohol): A Additio Polymer catalyst heat 2 2 x poly(viyl alcohol) liear chai polymer, x = Add a cross-liker: borax, B (forms covalet crosslik) B B " 2 B 2 viscoelastic B 2 EM 112 LSVDS Materials 21 rosslikig with Metal Ios 2 Sodium algiate + al 2 $ Top view EM 112 LSVDS Materials 22

12 Silicoes codesatio polymers #!chais of alteratig silico ad oxyge atoms with orgaic substituets o the silico. Moomer: silico compoud with orgaic groups () attached. 2 Sil 2 Example: dichlorodimethylsilae [( 3 ) 2 Sil 2 ] with water ( 2 ). The silicoe formed is dimethylsiloxae. Silicoes are either rubbers or oils depedig o the chai legth ad degree of cross-likig. Lubricats ar polish Gaskets, sealats Waterproofig (orgaic groups form barrier) EM 112 LSVDS Materials 23 ross-likig Affects Properties of Silicoes Properties of Silicoes Notoxic, stable, ureactive lame-resistat hydrocarbo substituets act to repel water. Properties deped o: 1)! -group 2)! hai legth 3)! Degree of cross-likig! No crossliks; liquid silicoe oils high T lubricats, hot oil baths! ew cross liks; silicoe rubber caulkig material! More cross liks; silicoe resis coatigs ad adhesives! All cross liks; Si 2 = quartz EM 112 LSVDS Materials 24

13 Summary: What holds polymers together? 1)! 2)! 3)! 4)! 5)! EM 112 LSVDS Materials 25 Uses of Polymers i Smart Sesors Polymers play a importat role i moder sesors Polyviylidee luoride (PVD) is oe of the mai polymers used to make smart sesors. Moomer: Polymer: Whe a film of PVD is stretched, the atoms alig o top ad the atoms o the bottom, producig a vertical dipole momet. The dipole momet i PDV gives it piezoelectric properties. The piezoelectric effect is the ability of a material to produce a voltage whe subject to mechaical stress. The stretched PVD film ca be attached to electrodes. Bedig the film will produce a voltage by faig out the dipole momets. EM 112 LSVDS Materials 26

14 ther Piezoelectric Polymers PVD is ot the oly polymer that is piezoelectric. Polyviyl luoride (PV): Moomer: Polymer: Polytrifluoroethylee (PTI) Moomer: Polymer: Properties of Piezoelectric Polymers The moomer must be polar. The atoms boded to the polymer backboe must be small. luorie is commo i piezoelectric polymers because of its size ad electroegativity. EM 112 LSVDS Materials 27 Biological Polymers 1. DNA, NA Moomers: ucleotides eact via codesatio polymerizatio DNA ad NA are polyesters (of 3 P 4 ). 2. Proteis Moomers: amio acids eact via codesatio polymerizatio Proteis are polyamides. Amio Acid Moomers: N + + N N Product: Protei N N N amide likage or peptide bod EM 112 LSVDS Materials 28

15 Structure of Proteis Secodary structure of proteis: Tertiary structure (protei foldig) is eve more complex. This structure is importat i protei activity. EM 112 LSVDS Materials 29 DNA (Deoxyriboucleic Acid) Moomer; ucleotide NA (iboucleic Acid): Polymer; polyucleotide EM 112 LSVDS Materials 30

16 ydroge Bodig i DNA EM 112 LSVDS Materials 31 rosslikig i DNA: What kid of forces? DNA replicatio EM 112 LSVDS Materials 32

17 Biomaterials are ay materials that have biomedical applicatios. or example, the materials that are used to fill teeth are biomaterials. haracteristics of Biomaterials Biocompatiblity: The body s immue system must ot attack the biomaterial. Physical requiremets: Differet for each specific eviromet. or example, artificial heart valves must ope ad close 70 to 80 times per miute. hemical requiremets: Biomaterials must be of medical grade. Must be biodegradable or o-reactive: beware of fillers, stabilizers, etc. EM 112 LSVDS Materials 33 Polymeric Biomaterials The degree to which the body tolerates foreig materials depeds o the ature of the atomic groups i the material. Naturally occurrig biomaterials are polymers of sugars (polysaccharides), ucleotides (NA, DNA) ad amio acids (proteis, ezymes, etc.). Types of Polymers Plastic: materials that ca be formed ito shapes. Thermoplastic: materials that ca be shaped more tha oce. (Used as replacemets for blood vessels.) Thermosettig: materials that ca oly be shaped oce (Used i detal devices, ad orthopedics such as hip replacemets.) Elastomer: material that is elastic i some way. If a moderate amout of deformig force is added, the elastomer will retur to its origial shape. Used as catheters, ad for coverig leads o implated electroics, like pacemaker. EM 112 LSVDS Materials 34

18 Examples of Biomaterial Applicatios eart eplacemet ad epairs: Polyethylee terephthalate, called Dacro, is ofte used i the maufacture of artificial heart valves. Dacro is used because tissue will grow through a polyester mesh. Vascular grafts: A vascular graft is the replacemet for a piece of blood vessel. Dacro is used for large arteries. Polytetrafluoroethylee, is used for smaller vascular grafts. EM 112 LSVDS Materials 35 Examples of Biomaterial Applicatios Artificial Tissue: Artificial ski, which is grow i the laboratory, is used to treat patiets with extesive ski loss. The challege with growig artificial ski is gettig the cells to alig properly. Therefore a scaffold must be used for the cells. The most successful scaffold is lactic acidglycolic acid copolymer. ip eplacemets: About 200,000 total hip replacemets are performed each year. A metal ball, a cobalt chromium alloy, is ofte used i a hip replacemet. This alloy is attached to a titaium alloy ad cemeted usig a tough thermoset polymer. The acetabulum, which accommodates the femur, is lied with a polyethylee layer EM 112 LSVDS Materials 36

19 You made it through hem 112! ogratulatios! Now, go ace that fial!