Modern Polymer Spect..

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3.19 A Worked E.xuniple 191 Figure 3-55. Sketch of assumed locations of selectively deuterated chains of n-nonadecane (2D2 arid 10D2, see text) in the orthorhombic crystal. - -5Hz- $ D z - ~ H ~ Conclusion no. 4 The process of melting can be described in the following way: the tvuizs-planar structure of the fraiu chains collapses (observations (i), (j) and (t)) and conformational disorder takes place accompanied by the appearance of the following conformational defects: GG, GTG, GTG’ (observations (j) and (l)), end-gauche (observation (u)) and gauche in general (observations (b), (t), (y), (v), (w), and (x)). In practice we find characteristic signals of liquid-like structures. With the aid of the selectively deuterated species 2D2 and 10D2 further details on the processes of solid-solid phase transition and melting can be derived. First, we consider the 2D2 molecule. Of necessity, the process of packing of traizsplanar chains to forni an orthorhonibic crystalline lamella cannot distinguish deuterated and undeuterated chain ends; the resulting lamella can be described by a random distribution of ‘up’ or ‘down’ chains (Figure 3-55). With such chains we can distinguish the conformational behavior of the heads and/or the tails of the chains. It becomes thus possible to be sure of the origins of the signals coming from conformational defects. The most direct information comes from the frequencies of the CD? rocking which have been calculated with normal coordinate calculations and are reported in Table 3.1. The infrared spectrum of 2D2 in the 670-600 cm-’ range shows only a band near 620 cm-’ below To (Figure 3-56). The band is not split, as mentioned above, because the precise phase coupling is lost by the random distribution of ‘up’ and ‘down’ chains. At the solid-solid transition a very weak additional band appears near 655 cm-’ (Figure 3-56) indicating the formation of gauche conformations at the deuterated chain ends, thus reiterating what has been already learned from C19. From a quantitative measure of the absorption intensities of the these modes it transpires that approximately 25% of chain ends are conformationally distorted. The infrared spectrum of 10D2 provides further information (Figure 3-57]. For the orthorhonibic phase the line near 620 c1n-l is split because in this case the phase coupling is achieved since translational symmetry is obtained within the crystal. At
30.5 'C Figure 3-56. Temperature dependence of the infrared \..:-A 3, 6.C spectrum of n-nonadecane-2D2 through orthorhombic + c( + phase transitions. Notice that (i) in the a phase a small number of deuterated chain heads has taken up the L.:-32Pc TG conformation which increases dramatically in the I " " ' J melt, (ii) in the melt a certain number of deuterated chains 700 660 620 580 v cm-1 do not tilt their heads but still keep the TT conformation. T, the doublets disappear since chains move and become uncorrelated (isolated). Since no absorption is observed near 655 and 677 cn-' it means that in the middle no conformational distorsions are generated in the a phase. The liquid-like structure is, however, observed at the melting. Conclusion no. 5 The final model emerging from this part of the study is the following: starting from a regular and ordered orthorhombic structure in which all tmns-planar chains are
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Modern Polymer Spectroscopy Edited
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Modern Polymer Spectroscopy Edited
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Preface For unfortunate reasons the
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However, theory and calculations yi
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Contents 1 Two-Dimensional Infrared
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Con ten t~ xi Index 5.2 Force Field
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Contributors M. Del Zoppo Dipartime
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1 Two-Dimensional Infrared (2D IR)
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1.2 Brick~qrorrnrl 3 . Figure 1-3.
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1.0 , Figure 1-6. The in-phtrse and
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1.2 Bcrckgroinizd 7 where AA (i~) i
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1.2 Background 9 1.2.5 Two-Dimensio
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1.3 Bnsic Properties of 20 IR Corre
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2D IR spectrometer coupled with a d
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1.5 Applirtrtions 15 Unlike a dispe
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\ '\ Melliyleiie 1'7- -3000 Posiliv
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11 Amorphous Crystalline ,...." I F
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1.5 Applications 21 / I 1430 Figure
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1.5 Appliccitioiis 23 Methylene Fig
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1.5 Ajqdicrrtions 25 3024 Figure 1-
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1.5 Applicutions 27 Furthermore. th
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1.7 Coizclirsions 29 derived in a s
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1.9 References 31 [9] Colthup, N. B
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2 Segmental Mobility of Liquid Crys
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SRMPLE/DETECTOR e3 ‘retardation
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2.4 Srvuc me-Dependenr Alignment 37
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2.5 Electric Field-Innductid Orirnt
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2.5 Electric Field-nclticetl Orient
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a -@ COWER SRHPLE ._ 2.5 Elec tric
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2.5 Electric Field-Itzduced Orienta
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2.5 Electric Field-IwrElrced Orient
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2.5 Electric Field-Im/irced Orientu
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2.5 Electric Field-Induced Orientli
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2.5 Electric Field-Induced Orientat
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2.5 Electric Field-Induced Orienfat
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2.5 Elrc tric Field-Iiidircwl Orim
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2500 2008 I s00 WRVtNdMRtR CM-I Fig
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-3.6 Aligmient OJ' Side- Clinin Liy
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~ polyester 2.6 Alignnient qf Side-
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I." 0.9 0.8 Figure 2-34. FTlR 0.7 p
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induced alignment of the investigat
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2.7 Orientation oj Liquid Ci:i,stal
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2.7 Orieritation of Liquid Ciysttrl
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0 8 18 16 1 a W u z a m a 0 Ln m Q
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2.7 Orientation oj Liquid Crystals
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2.7 Orientation of Liquid Crjvtals
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2.7 Orientatioiz of Liquid Crystals
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2.8 Conclusions 81 strain. As A0 is
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3. I0 Refcreiice.r 83 [I 71 Hoffina
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2.10 References 85 [92] Wiesner, U.
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t Order/Disorder in Chain Molecules
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onds which hold atoms together thro
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3.2 The Dyriamical Case qf Simll ar
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3.2 The Dyrinniical Case of Sinnll
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3.4 S11or.f- and Loizg-Rcrizye Vibr
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3.4 Slzort- and Loiig-Range Vibrati
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eyularity), e.g., 2. During the pol
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3.5 Towards Lnrger Molecules: From
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3.5 TOIIYW~ Laiyer Molertiles: Fvoi
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3.5 Towmu" Larger Molecules: F~om O
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1700 - CIO --- ca c 22 _- c 12 l l
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3.6 From Dynamics to Vibrational Sp
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3.6 Froin Dynaiiiics to T’ihratio
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3.7 The Case of Isotactic Polypropy
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3.7 The Cuse of Isotactic Polypvop.
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3.8 Density of Vibrational States a
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3.8 Dtvz.sit,v of L’ihrntioizal S
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3.8 Driisity of Vibratioiid StLitrs
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3 9 Mouiiiq ToIvmds Rerrlitv: From
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3.9 Moving Towards Reality: From Or
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3.9 Moving Towards Reality: Froin O
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3.10 Wlmt Do We Learn from Cnlcailc
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+ 3.11 A Very Siriiple Ccrse: Latti
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3 I1 A Yey) Siiiiple Case: LLittice
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3.11 A Vq> Siiiiplc Crrw: Luttice D
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Figure 3-22. Sample eigenvectors in
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3.12 CIS-trans Opening @the Double
Page 156 and 157: 3.13 Defect Modes cis Structtrr.al
Page 158 and 159: 3.13 Defect Mo&s cis Structurcil Pr
Page 160 and 161: 0 3.14 Case Studies N 0 d - Y N o m
Page 162 and 163: 3.14 Case Studies 147 OC 60 58 57.
Page 164 and 165: 3.14 Case Studies 149 GI A V E N U
Page 166 and 167: 3.14 Case Studies 15 1 correspond t
Page 168 and 169: 3.14 Case Studies 153 (I10 + 200) +
Page 170 and 171: 3.14 Case Studies 155 1500 1480 146
Page 172 and 173: 3.14 Case Studies 157 the molecular
Page 174 and 175: 17E (ir 1, R): (iii) z = 4, t = 1,
Page 176 and 177: 3.16 Stnictural Znlioi~zogeneity an
Page 178 and 179: 3.1 7 Fermi Resonancrs 163 stants.
Page 180 and 181: 3.1 7 Femi Resorinnces 165 2 L 1 29
Page 182 and 183: lowing. The CHl-bending mode 6 [cer
Page 184 and 185: 3.17 Ferini Re.sonrriire.s 169 a Fi
Page 186 and 187: 3. I7 Fernii Resoiiances 17 1 terin
Page 188 and 189: 3.18 Band Broadening and Confonnati
Page 190 and 191: 3.18 Bmd Brourleiziriy md Cmforrnat
Page 192 and 193: 3.18 Band Bvoaderiing arid Conjonna
Page 194 and 195: 3.18 Band Broadening and Confornmti
Page 196 and 197: 3.19 A Worked E.utinple 181 pre-mel
Page 198 and 199: 3.19 A Wovh-ecl E.uanzple 183
Page 200 and 201: 3.19 A Worked Example 185 19 5°C 2
Page 202 and 203: 3.19 A Workrd Example 187 Figure 3-
Page 204 and 205: 3.19 A Worked E.rcnniplr 189 LAM I
Page 208 and 209: 3.19 A Worked E.vnn~yle 193 Figure
Page 210 and 211: 3.19 A Worked E.vnrqde 195 009.1 00
Page 212 and 213: 3.19 A Worked Example 197 existence
Page 214 and 215: 3.1 9 A Worked Example 199 The soli
Page 216 and 217: 3.20 References 201 very important,
Page 218 and 219: 3.20 References 203 [41] M. Gussoni
Page 220 and 221: 3.20 Refeeveiicrs 205 [I 171 P. Jon
Page 222 and 223: 4 Vibrational Spectroscopy of Intac
Page 224 and 225: 4.3 Georrietvy oj Intuct Po1vniev.r
Page 226 and 227: 1'45 4.4 Geometric Chunges I?zditce
Page 228 and 229: 4.4 Geometric Chmges Iiid~lrcecl bj
Page 230 and 231: 4 5 Mer1iodolog.v of Raiii~11 Studi
Page 232 and 233: 4.7 Poly(p-pheiq.lene) 217 with an
Page 234 and 235: 4.7 Pol)~(p-pheiz~~lene) 219 ENERGY
Page 236 and 237: is worthwhile pointing out that the
Page 238 and 239: ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 801 Table 4-3
Page 240 and 241: 4.7 Poly(y-phenylene) 225 Figure 4-
Page 242 and 243: Table 4-4. Observed Raman frequenci
Page 244 and 245: 4.8 Other Polwieys 229 Table 4-5. T
Page 246 and 247: under various models. According to
Page 248 and 249: 4. I0 Mechnriism oj Charge. Transpo
Page 250 and 251: 4.12 Reftrences 235 [ 131 Kuzmany,
Page 252 and 253: 4.12 References 237 [98j Matsunuma,
Page 254 and 255: 5 Vibrational Spectroscopy of Polyp
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5.2 FOYCC Fields 241 such calculati
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5.2 Force Fields 243 accounts for o
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5.2 Force Fields 245 centers of the
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5.2 Force Fields 247 ture with conf
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5.3 Amide Modes 249 to the nh initi
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5.3 Ainide Modes 251 Table 5-1. Ami
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Table 5-2. Some amide modes of four
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5.3 Amidc Modes 255 Figure 5-1. Opt
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5.4 Polypeptides 257 nonhydrogen-bo
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5.4 Polvpeptida 259 Figure 5-2. Ant
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I 5.4 Polypeptides 261 )I .- + $ 80
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1226M 1222s (1 1165W 1167s (1 1120V
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135s 9 1 Ms1i 122Wbr 147 NH ob(37)
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5.4 Polypeptides 267 glycine residu
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5.4 Polypeptides 269 Raman bands in
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5.4 Polypeptides 271 Figure 5-7. St
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Frequency (cm-'1 100% b 700 500 300
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5.4 Polypptidt~s 215 Table 5-9. Obs
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~~ ~~ ~~~ ~ ~ ~~ 5.4 Polypeptides 2
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5.4 Poliyeptides 219 Table 5-11. Co
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Table 5-12. Aniide mode frequencies
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1351 Lifson, S., Stern, P. S., J. C
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5.6 Refeverices 285 [130] Tiffany,
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Index Amide modes 249 Amorphous pol
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Step-scan FTIR spectroscopy 14,34 -
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