Modern Polymer Spect..

More documents

Recommendations

Info

2.8 Conclusions 81 strain. As A0 is an experimentally determined parameter based on a uniaxial orientation model whose value should represent the intensity of an absorption band exclusive of orientation effects, the anomalous increase of the structural absorbance during elongation-where the sample thickness actually decreases-points towards an invalidity of the uniaxial syinmetry. T~us, the geometries a and b of Figure 2-52 can be excluded on the basis that both would lead to a decrease of A" during elongation. The occurrence of the structural model c at the inversion point of the order parameter has first been proposed on the basis of small-angle X-ray measurements by Finkelinann and Kiipfer [117]. Thus, the appearance of four diffraction maxima have been explained in terms of a biaxial, planar orientation of the mesogens in the film plane (Figure 2-52c). Depending on the inclination angle of the mesogens with the stretching direction, such a transition state would lead to an order parameter close to zero and could also explain the anomalous behavior of the structural absorbance [36]. In conclusion, it could be shown that, during elongation of the anisotropic LSCE network, the network structure changes from a uniaxial symmetry perpendicular to the applied mechanical field (parallel to the orientation induced in the second crosslinking step) via a planar-biaxial model (inversion of the order parameter) to a system aligned in the stretching direction of the rheo-optical experiment [36]. Simultaneously, the originally transparent polymer becomes opaque at the inversion point of the order parameter and turns transparent again upon reorientation of the mesogens into the machine direction. 2.8 Conclusions The aim of this contribution was to demonstrate the potential of FTIR/FTNIR polarization spectroscopy at variable temperatures for the characterization of segmental mobility in liquid crystals and liquid-crystalline polymers under the influence of external fields. Selected examples have been discussed, where either timeresolved measurements or static experiments have been utilized to monitor the effects of electric, electroniagnetic, or mechanical perturbations on the liquidcrystalline system under investigation. For the extremely fast, reversible switching processes of low-molecular weight liquid crystals and side-chain liquid-crystalline polymers in electric fields, the novel step-scan FTIR technique has been applied. The selective character of vibrational spectroscopy generally allowed us to separate the orientational effects in different functionalities of the liquid-crystalline compound. Thus, side-chain liquid-crystalline polymers, for example, have been characterized under the influence of different external fields in terms of the relative alignment of their main chain, spacer, and mesogenic groups, respectively. Although the presented data are necessarily limited to selected examples, the variety of information and its detailed quantitative Character demonstrate, that FTIR/FTNIR polarization spectroscopy has certainly become an extremely valuable tool lo elucidate the dynamics of segmental motion in liquid-crystalline systems.
82 3 Segmental Mobility of Liquid CrVstLiIs und Liqziicl-Cr!).stalline Poljjmer-s 2.9 Acknowledgments The authors would like to thank Prof. Dr. H. Finkelmann and Dr. J. Kiipfer (University of Freiburg, Germany), Prof. Dr. R. Zentel and Dr. T. Oge (University of Wuppertal and University of Mainz, Germany), Prof. Dr. B. Jordanov (University of Sofia, Bulgaria), Dr. N. C. R. Holm, Dr. S. Hvilsted, Dr. M. Pedersen and Dr. P. S. Rainanujam (Riso National Laboratory, Denmark), Dr. F. Andruzzi (CNR, Pisa, Italy), Dr. M. Paci, Dr. E. L. Tassi and Prof. Dr. P.-L. Magagnini (University of Pisa, Italy), and Dr. E. Happ (University of Ulm, Germany), Dr. C. Hendaiin (Deutsche Post, Darmstadt), Dr. M. Czarnecki (University of WroclaLy, Poland) for helpful discussions, individual experimental and theoretical data, and the supply of polymer samples. Financial and instrumental assistance by the Deutsche Forschungsgenieinschaft, Bonn, Germany, the Ministerium fur Wisseiischaft und Forschung, Dusseldorf, Germany, Fonds der Cheinischen Industrie, Frankfurt, Germany, and the European Community via contract BRE2.CT93.0449 is also gratefully acknowledged. 2.10 References [I] Vertogen G., de Jeu, W. H., T/iennotro/iic Liquid Crystcils, F~rthmerzt~d~, Berlin: Springer Verlag, 1987. [2] Koswig, H. D., Fli e Kri:r.istalki~, Berlin: VEB Verlag, 1984. [3] Donald, A. M., Windle. A. H., Lipid Crystallirze Polytners, Cambridge: Cambridge University Press, 1992, pp. 38-41. [4] Finkelmann, H., in: Lipid Crj~~rallinirv Pol,yniers: Prirrcrjhs mid Atntkiriierird Pwprrirs: Ciferri, A. (Ed.), Weinheim: VCH Verlagsgesellschaft, 1991; pp. 315. [5] McArdle, C. B., in: Side Chain Liquid Crystal Polymers: McArdle, C. B. (Ed.), Glasgow: Blackie & Son Ltd., 1989; pp. 357. [6] Wendorff, J. H., Eich, M.. Mol. Cryst. Liq. Cryst. 1989, 169, 133-166. [7] Ndkamura, T., Ueno, T., Tani, C., Mol. Cryst. Liq. Cryst. 1989, 169, 167-192. [8] Demus, D., Goodby, J., Gray, G. W., Spiess, H.-W., Vil, V. (Eds.), H~~rirlDooX o/ Liqid Crystals, Weinheim: Wiley-VCH, 1998. [9] Carfagna, C. (Ed.), Lipid Crystalline Polymers, Oxford: Pergamon, 1994. [lo] Chilton, J. A., Gossey, M. T. (Eds.), Special Po/j3rners ,/ijr Electronic cititl O/~roe/~,c~rro~iic.s, London: Chapman & Hall, 1995. [ll] Kelly, S. M., Liq. Cryst. Today 1996, 6(4), 1. [I?] Schadt, M. in: Lipid Crystal.y: Baunigartel, H., Frank, E. U., Grunsbein, W. (Eds.), Stegenieyer, H. (Guest Ed), New York: Springer, 1994, Chapter 8, p. 195. [ 131 Chilton, J. A,, Gossey, M. T. (Eds.), Special Pol~~mers ,for Elecfronics crritl Opto-electrotiics, London: Chapman & Hall, 1995. [ 141 Siesler, H. W., Holland-Moritz., K., Zr?/iar.ed crnd Rtrriinrz S{)t~c.fr.u,scopjJ of Poljwiets, New York: Marcel Dekker, 1980. [15] Hvilsted, S., Andruzzi, F., Kulinna, C., Siesler H. W., Ramanujam, P. S.? i~~icroriiole~~~rlc..r. 1995,-?8, 2172. 1161 Shilov, S.. Okretic, S., Siesler. H. W., Czarnecki, M. A., Appl. Spectrosc. Reus., 1996, 31 (1&2), 125-165.
Page 2 and 3:
Modern Polymer Spectroscopy Edited
Page 4 and 5:
Modern Polymer Spectroscopy Edited
Page 6 and 7:
Preface For unfortunate reasons the
Page 8 and 9:
However, theory and calculations yi
Page 10 and 11:
Contents 1 Two-Dimensional Infrared
Page 12 and 13:
Con ten t~ xi Index 5.2 Force Field
Page 14 and 15:
Contributors M. Del Zoppo Dipartime
Page 16 and 17:
1 Two-Dimensional Infrared (2D IR)
Page 18 and 19:
1.2 Brick~qrorrnrl 3 . Figure 1-3.
Page 20 and 21:
1.0 , Figure 1-6. The in-phtrse and
Page 22 and 23:
1.2 Bcrckgroinizd 7 where AA (i~) i
Page 24 and 25:
1.2 Background 9 1.2.5 Two-Dimensio
Page 26 and 27:
1.3 Bnsic Properties of 20 IR Corre
Page 28 and 29:
2D IR spectrometer coupled with a d
Page 30 and 31:
1.5 Applirtrtions 15 Unlike a dispe
Page 32 and 33:
\ '\ Melliyleiie 1'7- -3000 Posiliv
Page 34 and 35:
11 Amorphous Crystalline ,...." I F
Page 36 and 37:
1.5 Applications 21 / I 1430 Figure
Page 38 and 39:
1.5 Appliccitioiis 23 Methylene Fig
Page 40 and 41:
1.5 Ajqdicrrtions 25 3024 Figure 1-
Page 42 and 43:
1.5 Applicutions 27 Furthermore. th
Page 44 and 45:
1.7 Coizclirsions 29 derived in a s
Page 46 and 47: 1.9 References 31 [9] Colthup, N. B
Page 48 and 49: 2 Segmental Mobility of Liquid Crys
Page 50 and 51: SRMPLE/DETECTOR e3 ‘retardation
Page 52 and 53: 2.4 Srvuc me-Dependenr Alignment 37
Page 54 and 55: 2.5 Electric Field-Innductid Orirnt
Page 56 and 57: 2.5 Electric Field-nclticetl Orient
Page 58 and 59: a -@ COWER SRHPLE ._ 2.5 Elec tric
Page 60 and 61: 2.5 Electric Field-Itzduced Orienta
Page 62 and 63: 2.5 Electric Field-IwrElrced Orient
Page 64 and 65: 2.5 Electric Field-Im/irced Orientu
Page 66 and 67: 2.5 Electric Field-Induced Orientli
Page 68 and 69: 2.5 Electric Field-Induced Orientat
Page 70 and 71: 2.5 Electric Field-Induced Orienfat
Page 72 and 73: 2.5 Elrc tric Field-Iiidircwl Orim
Page 74 and 75: 2500 2008 I s00 WRVtNdMRtR CM-I Fig
Page 76 and 77: -3.6 Aligmient OJ' Side- Clinin Liy
Page 78 and 79: ~ polyester 2.6 Alignnient qf Side-
Page 80 and 81: I." 0.9 0.8 Figure 2-34. FTlR 0.7 p
Page 82 and 83: induced alignment of the investigat
Page 84 and 85: 2.7 Orientation oj Liquid Ci:i,stal
Page 86 and 87: 2.7 Orieritation of Liquid Ciysttrl
Page 88 and 89: 0 8 18 16 1 a W u z a m a 0 Ln m Q
Page 90 and 91: 2.7 Orientation oj Liquid Crystals
Page 92 and 93: 2.7 Orientation of Liquid Crjvtals
Page 94 and 95: 2.7 Orientatioiz of Liquid Crystals
Page 98 and 99: 3. I0 Refcreiice.r 83 [I 71 Hoffina
Page 100 and 101: 2.10 References 85 [92] Wiesner, U.
Page 102 and 103: t Order/Disorder in Chain Molecules
Page 104 and 105: onds which hold atoms together thro
Page 106 and 107: 3.2 The Dyriamical Case qf Simll ar
Page 108 and 109: 3.2 The Dyrinniical Case of Sinnll
Page 110 and 111: 3.4 S11or.f- and Loizg-Rcrizye Vibr
Page 112 and 113: 3.4 Slzort- and Loiig-Range Vibrati
Page 114 and 115: eyularity), e.g., 2. During the pol
Page 116 and 117: 3.5 Towards Lnrger Molecules: From
Page 118 and 119: 3.5 TOIIYW~ Laiyer Molertiles: Fvoi
Page 120 and 121: 3.5 Towmu" Larger Molecules: F~om O
Page 122 and 123: 1700 - CIO --- ca c 22 _- c 12 l l
Page 124 and 125: 3.6 From Dynamics to Vibrational Sp
Page 126 and 127: 3.6 Froin Dynaiiiics to T’ihratio
Page 128 and 129: 3.7 The Case of Isotactic Polypropy
Page 130 and 131: 3.7 The Cuse of Isotactic Polypvop.
Page 132 and 133: 3.8 Density of Vibrational States a
Page 134 and 135: 3.8 Dtvz.sit,v of L’ihrntioizal S
Page 136 and 137: 3.8 Driisity of Vibratioiid StLitrs
Page 138 and 139: 3 9 Mouiiiq ToIvmds Rerrlitv: From
Page 140 and 141: 3.9 Moving Towards Reality: From Or
Page 142 and 143: 3.9 Moving Towards Reality: Froin O
Page 144 and 145: 3.10 Wlmt Do We Learn from Cnlcailc
Page 146 and 147:
+ 3.11 A Very Siriiple Ccrse: Latti
Page 148 and 149:
3 I1 A Yey) Siiiiple Case: LLittice
Page 150 and 151:
3.11 A Vq> Siiiiplc Crrw: Luttice D
Page 152 and 153:
Figure 3-22. Sample eigenvectors in
Page 154 and 155:
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 206 and 207:
3.19 A Worked E.xuniple 191 Figure
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
Page 256 and 257:
5.2 FOYCC Fields 241 such calculati
Page 258 and 259:
5.2 Force Fields 243 accounts for o
Page 260 and 261:
5.2 Force Fields 245 centers of the
Page 262 and 263:
5.2 Force Fields 247 ture with conf
Page 264 and 265:
5.3 Amide Modes 249 to the nh initi
Page 266 and 267:
5.3 Ainide Modes 251 Table 5-1. Ami
Page 268 and 269:
Table 5-2. Some amide modes of four
Page 270 and 271:
5.3 Amidc Modes 255 Figure 5-1. Opt
Page 272 and 273:
5.4 Polypeptides 257 nonhydrogen-bo
Page 274 and 275:
5.4 Polvpeptida 259 Figure 5-2. Ant
Page 276 and 277:
I 5.4 Polypeptides 261 )I .- + $ 80
Page 278 and 279:
1226M 1222s (1 1165W 1167s (1 1120V
Page 280 and 281:
135s 9 1 Ms1i 122Wbr 147 NH ob(37)
Page 282 and 283:
5.4 Polypeptides 267 glycine residu
Page 284 and 285:
5.4 Polypeptides 269 Raman bands in
Page 286 and 287:
5.4 Polypeptides 271 Figure 5-7. St
Page 288 and 289:
Frequency (cm-'1 100% b 700 500 300
Page 290 and 291:
5.4 Polypptidt~s 215 Table 5-9. Obs
Page 292 and 293:
~~ ~~ ~~~ ~ ~ ~~ 5.4 Polypeptides 2
Page 294 and 295:
5.4 Poliyeptides 219 Table 5-11. Co
Page 296 and 297:
Table 5-12. Aniide mode frequencies
Page 298 and 299:
1351 Lifson, S., Stern, P. S., J. C
Page 300 and 301:
5.6 Refeverices 285 [130] Tiffany,
Page 302 and 303:
Index Amide modes 249 Amorphous pol
Page 304 and 305:
Step-scan FTIR spectroscopy 14,34 -
show all

Modern Polymer Spect..

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?