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1 9 th Interntionl Conference on Quntittive InfrRed Thermogrphy July -5, 008, Krkow - Polnd Two-dimensionl therml nlysis of orgnic mterils y micro-scle thermogrphy *Tokyo Institute of Technology, O-okym, Meguro-ku,Tokyo , Jpn ** Eto Denki,Co. Ltd., Shinkw, Mitk, Tokyo , Jpn *** i-phse, Co. Ltd., Oski, Shingw, Tokyo 4-006, Jpn y J. Morikw*, E. Hykw***, T.Eto**, T. Hshimoto* Astrct. n lknes hve een widely studied s model mteril of lipids, liquid crystls, ftty cids, the cell memrne, nd polymers. It is known tht its complicted phse trnsition corresponds to the functions of these mterils. The methods of X-ry diffrction, IR spectroscopy, nd DSC (Differentil scnning clorimetry) re generlly used to study the phse trnsitions of n- lknes, however, few thermo-grphicl mesurements hve een done. This study gives new oservtion on phse trnsitions nd structure formtion processes of n- lkne y using high-speed IR cmer with n InS focl plne rrys on the sis of method of micro-scle two-dimensionl therml nlysis. The dvntge of this technique is micro-scle sptil resolution (μm) nd high-speed dt storge. The forerunning phenomenon of phse trnsition ws visulized s the sptil temperture fluctution y two-dimensionl differentil clculus. The differences of the sptil inhomogeneity of proceeding speed of crystlliztion nd rottor phse trnsitions were nlyzed on n- pentcosne, n- tetrcosne, nd n- tricosne.. Introduction The odd nd even numer effect of phse ehviour of orgnic moleculr crystls of n- lknes hs een investigted in detil y vrious mesuring techniques for its importnce s model mteril of functionl device in electronic industry, or s model of phospholipids ilyer nd ftty cids in iophysicl sciences. However, the het trnsport properties such s therml diffusivity nd therml conductivity of n- lknes in solidsolid phse trnsition nd crystlliztion under the exothermic ltent het hve not yet een sufficiently studied. Two-dimensionl micro scle therml nlysis [-4] for the mesurement of ltent het tht is relesed from the freezing iologicl cells ws exmined in detil y use of high-speed nd micro-scle IR imging technique. The thermo grphiclly oserved ltent het tht is spreding over the tissues llow estimting the therml properties of the cell memrne nd het source. The mgnifiction fctor of the IR micro-lens nd the dt-cpturing/storge speed re improved in this study. The quntittive therml nlysis of n odd nd n even numer n- lkne under temperture scn is exmined, which introduces new insight in the micro-scle therml nlysis of the erly stge of crystlliztion nd phse trnsitions of n- lkne from the viewpoint of het trnsfer nd its reltionships with the structure ppernces.. Experimentl.. IR thermogrphy A high-speed IR cmer, Phoenix (Indigo), hving n indium-ntimony (InS) sensor rry of 0x56 pixels with the optimum wvelength etween μm nd 5μm, ws used for tking the micro-scle thermogrphy with the originlly designed silicon germnium mde microscopic lens with mgnifiction of x0, x7 nd x, corresponding to the re size of 0.96 mm x 0.77mm,.8 mm x.0 mm, nd 4mm x mm, with the sptil resolution of.0 μm x.0 μm, 4.0 μm x 4.0 μm, 4 μm x 4 μm, respectively. The frme rte for tking n imge ws selected 60 ~ 000 frmes/s (6.7msec~msec per one picture) in this study. The length nd distortion re clirted y using stndrd micro-scle of USAF 95. The intensity ws clirted with the 8ch dt logger y mesuring the electric current of temperture sensor.. A precision temperture control of micro lignement specimen stge Temperture control of micro precision lignment xyz stge with pitch of μm ws electroniclly designed y using FPGA (Xilinx) technology. A constnt rte of heting nd cooling, 0. C/min-500 C /min is routinely used for therml nlysis in thermo-grphicl view.. n-lknes The n-lknes exmined in this studied re n- pentcosne (C 5H 5), n- tetrcosne (C 4H 50), nd n- tricosne (C H 48). The crystllogrphic structures of the rottor phse determined in X-ry diffrction re s follows.. n - pentcosne, C 5H 5 (crystl systems : orthorhomic -> hexgonl -> liquid). n - tetrcosne, C 4H 50 ( : monoclinic -> hexgonl -> liquid). n - tricosne, C H 48 ( : triclinic -> hexgonl -> liquid)

from I ( t) = I t = lim I (t) I (t t) t 0 t where I (t) is intensity, t is

A time differentil filter ws used to otin the time differentil imge y

ii) Discrete-time Fourier trnsform, G( n N ) = N g(k) exp j nk N N K =0

in one cycle. 4. Results nd discussion 4. n - tetrcosne, C 4H 50 Fig.

stte (60 C) to the solid stte (0 C) of n-lkne C 4H 50.

phse trnsitions (f). The time indicted y ech rrow in Fig.

The developing process of crystlline lmelle is oserved in Fig.

On the other hnd, the D differentil imges in Fig.

e Intensity /.u. 00 0800 0600 0400 c d e C4H50 000 0 5 0 5 0 f Fig.

2 9 th Interntionl Conference on Quntittive InfrRed Thermogrphy. Anlyticl procedure i) Time differentil Time differentil imges re clculted from I ( t) = I t = lim I (t) I (t t) t 0 t where I (t) is intensity, t is time, t is time intervl etween the cpturing. A time differentil filter ws used to otin the time differentil imge y selecting n optimum mtrix size. ii) Discrete-time Fourier trnsform, G( n N ) = N g(k) exp j nk N N K =0 where G(n/N) is discrete Fourier trnsformed function, nd N is smple numer in one cycle. 4. Results nd discussion 4. n - tetrcosne, C 4H 50 Fig. shows differentil therml nlysis (DTA) curve in cooling scn from the molten stte (60 C) to the solid stte (0 C) of n-lkne C 4H 50. The exothermic het is oserved t the crystlliztion (, c, d) nd the rottor phse trnsitions (f). The time indicted y ech rrow in Fig. corresponds to the thermo grphic imges (, c, d, f) nd the time differentil threedimensionl imges (, e) in Fig., in which the position for DTA nlysis is indicted s lck rrow. The developing process of crystlline lmelle is oserved in Fig.-d, succeeded y the rottor phse trnsitions in Fig.f. On the other hnd, the D differentil imges in Fig. nd e show the sptil temperture Intensity /.u c d e C4H f Fig.. Time development of photon-count intensity detected on selected pixel (shown s lck rrow in Fig.) of IR-FPA in the process of crystlliztion nd rottor phse trnsition of C 4H 50 in rpid cooling (-60 C/min) mesurement. c e x d f x 0 μm Fig.. Differentil imges of temperture distriution t the moment of () crystlliztion nd (e) rottor phse trnsition. IR microphotogrphs in the process of crystlliztion (, c, d) nd rottor phse trnsition (f) of C 4H 50 in rpid cooling mesurement. Alphets correspond to the rrows in Fig..

MICROSCALE APPLICATIONS fluctution moment efore n occurrence of crystlliztion nd rottor phse trnsition, which ffects the structure developing process.

Therml diffusivity of C 4H 50 shows step increse from the liquid to hexgonl, nd to monoclinic crystl systems. The phse trnsitions in Fig., nd e strted on the different sis of therml diffusivity, 0.

With n dvntge of the smll mount of specimen, the time nd sptil differentil nlysis of highspeed thermogrphy gives the precise informtion of the structure developing process in view of the het trnsfer

n - pentcosne, C 5H 5 The process of growth of crystlline lmell of odd numer n- lkne C 5H 5 under cooling scn is clerly oserved y the micro-scle IR system with high mgnifiction lens. Fig.

In the sme mnner s oserved in Fig. the different exothermic het ptterns re seen in the crystlliztion nd the rottor phse trnsition. In crystlliztion (Fig.

. Differentil imges of exothermic het front of crystlline lmelle; () crystlliztion (liquid stte to hexgonl stte), () rottor phse trnsitions, nd (c) rottor phse trnsition (hexgonl to monoclinic) in

3 MICROSCALE APPLICATIONS fluctution moment efore n occurrence of crystlliztion nd rottor phse trnsition, which ffects the structure developing process. For exmple, in the liquid-solid phse trnsition in Fig. the temperture fluctution is loclized in contrst to the rpid nd homogeneous fluctutions oserved in solid-solid phse trnsition in Fig.e. Tking into ccount the therml diffusivity of C 4H 50 in etween phse trnsitions, mesured y temperture wve method [5], one of the resons for this phenomenon cn e explined. Therml diffusivity of C 4H 50 shows step increse from the liquid to hexgonl, nd to monoclinic crystl systems. The phse trnsitions in Fig., nd e strted on the different sis of therml diffusivity, 0.8x0-7 m s - in the liquid stte (Fig. ), nd.5x0-7 m s - in the hexgonl crystl stte (Fig. e). With n dvntge of the smll mount of specimen, the time nd sptil differentil nlysis of highspeed thermogrphy gives the precise informtion of the structure developing process in view of the het trnsfer nd therml properties. 4. n - pentcosne, C 5H 5 The process of growth of crystlline lmell of odd numer n- lkne C 5H 5 under cooling scn is clerly oserved y the micro-scle IR system with high mgnifiction lens. Fig. shows time differentil IR imge mesured in the crystlliztion (Fig. ) nd rottor phse trnsition (Fig., c). A right-color prt corresponds to the edge front of exothermic het on lmell formtion. In the sme mnner s oserved in Fig. the different exothermic het ptterns re seen in the crystlliztion nd the rottor phse trnsition. In crystlliztion (Fig. ) spindle-shped crystlline lmell is formed one y one, on the other hnd, in rottor phse trnsitions (Fig., c) the exothermic het front proceeds instntneously. c μ Fig.. Differentil imges of exothermic het front of crystlline lmelle; () crystlliztion (liquid stte to hexgonl stte), () rottor phse trnsitions, nd (c) rottor phse trnsition (hexgonl to monoclinic) in rpid cooling mesurement (-60 C/min) of C 5H 50. The spindle-shped lmelle size is out 0μm wide nd 60μm long. The mgnified imge of lmelle (in hexgonl stte) is shown in Fig. 4. The lmelle re ppered rndomly t first, nd then stcked nd overlpped with ech other, in the ppering order of 5 7, s schemticlly shown in Fig. 4c. The erly stge of ppernce of lmelle No. -5 is shown in Fig. 5 with the time differentil IR imges t every 6.7ms. Lmell ppers first, then lmell nd strts to grow, nd then they spred into rnches. c μ Fig. 4. The encircled re with frme in the differentil imge on crystlliztion of C 5H 50 () is mgnified s n IR imge of lmelle in (). The lmelle re numered -9 in (c). Fig.5 The lmell growth process oserved y c d differentil IR imge. ) lmell is ppered, ) lmell nd re ppered, c) lmell collides to lmell, nd lmell 5 is ppered, d) lmelle re in growth in different rnches.

4 9 th Interntionl Conference on Quntittive InfrRed Thermogrphy The micro-scle therml nlysis of ech lmell No.-5 cn e done with in situ nlysis of intensity profiles under cooling scn with the imges of Fig. -5. The therml nlysis long the growth direction (long xis) of lmell No. nd is shown in Fig. 6., Intensity / (.u.) Intensity / (.u.) Fig. 6 On-lmell therml nlysis of lmell in different time scle for crystlliztion nd phse trnsitions; () in the long time rnge, nd () in the shorter time rnge Intensity / (.u.) Intensity / (.u.) Fig. 7 The erly stge of lmell growth in different directions y the on-lmell therml nlysis. () long the long xis (in the direction of the lmell growth) nd () in the perpendiculr direction to the long xis of the lmell growth. The typicl intensity profiles of lmelle show three peks, which correspond to the three different exothermic het ptterns s oserved in Fig.. The st pek corresponds to the liquid-solid phse trnsition (crystlliztion), nd the nd nd rd correspond to the solid-solid phse trnsitions (rottor phse trnsitions). The erly stge of crystlliztion of lmell is re-plotted in Fig. 6. The different profiles cn e seen on ech different pixels on lmell, which indictes tht the inter-correltion of lmell with the surrounding temperture field is not simple. Different from the cse oserved in the iologicl cells []-[4], the structure (crystlline lmell) is newly formed in the temperture field with exothermic het. In Fig. 7 much erlier stge of crystlliztion is nlyzed in two different directions, in the growth direction of lmell (Fig. 7) nd in the perpendiculr direction to it (Fig. 7). The time dely of its rising prt of the st pek in Fig. 7 corresponds to the lmell growth in the long xis direction t ech locted pixel on lmell. The edge front of the lmell grows from the center to the oth end, ut nd only one DTA pek cn e found in this direction. On the other hnd, in the therml nlysis in the perpendiculr direction (Fig. 7), shifted pek is ppered definitely efore the occurrence of rottor phse trnsition. This nd pek is found s correlted with the widening of lmell in the perpendiculr direction to the long xis of the lmell growth. It is noteworthy to mention tht the micro-scle therml nlysis y IR imge cn detect the nisotropic lmell growth with time dely in different directions. 4. n - tricosne, C H 48 The exothermic het ptterns of odd numer n- lkne C H 48 is different from tht of C 5H 50. The spindle-type stright lmell formtion is not oserved in the crystlliztion, ut dot-like imge cn e oserved in the time differentil pttern (Fig. 8). On the other hnd, in the rottor phse trnsition stright shped lmell is clerly ppered (Fig. 8), ut in sprsely mnner. In ddition, re-crystlliztion of lmelle is clerly oserved under heting scn from the triclinic to the hexgonl phse (Fig. 8c). This unique growth pttern of exothermic het is ttriutle to the phse in hexgonl crystl of C H 48 tht cn e found y temperture wve nlysis [5,6]. The profile of micro-scle therml nlysis on lmell No.0 (Fig. 9), which is formed in the solid-solid phse trnsition from the hexgonl to triclinic phse, is shown in Fig. 9. In this cse the lmell is more isolted (Fig. 9) nd the temperture field outside the lmell cn e nlyzed. No exothermic het influence cn e detected

numericl nlysis to determine the het source term y the method of Cristophe et l. [7]. c μ Fig.

5 MICROSCALE APPLICATIONS in the distnce of 4 pixels from the lmell (lines No. & in Fig. 9), less thn 5 μm in this cse. The exothermic het of iologicl cells ws more influentil in the longer distnce (in the rnge of μm) nd this informtion would e helpful to evlute the correltion mtrix in the inverse prolem numericl nlysis to determine the het source term y the method of Cristophe et l. [7]. c μ Fig. 8 Differentil imges of exothermic het pttern in () crystlliztion, () rottor phse trnsition in cooling (-0 C/min), (c) rottor phse trnsition in heting (+0 Cmin) of C H 50. Intensity / (.u.) μm Fig. 9 () The intensity profiles in the growth process of lmell No.0 on the pixels long the direction of the rrow indicted in Fig. 9, () IR imge of n isolted lmell of C H 48 tht is ppered in the rottor phse trnsition in cooling, 5. Conclusion The exothermic het ptterns of the lmelle growth of n- lkne during phse trnsitions were otined y the high-speed micro-scle IR imging technique. The odd-even numer effect of rottor phse trnsition ws oserved y the different exothermic het pttern. It gives us new insight to understnd the lmelle growth process of phse trnsitions in micro-scle. To summrize the min point of this pper is s follows.. On-lmell micro-scle therml nlysis is shown on the odd nd even numer n-lkne.. The odd-even numer difference of the exothermic het ptterns on phse trnsitions is shown y the time differentil exothermic het pttern in micro-scle.. The nisotropic growth rte of the crystlline lmelle is found in the width nd the length directions. The micro-scle therml nlysis of IR cmer hs n dvntge to oserve the direction of diffusion of exothermic het nd this technique cn e pplied to vrious fields of mteril sciences in comintion with the numericl dt nlysis of the inverse prolem. REFERENCES [] T. Hshimoto, nd J. Morikw, Two-dimensionl therml nlysis on freezing of onion epiderml cell y highspeed infrred microscopic cmer, Jpn. J. Appl. Phys., 4 (00) L706-L708. [] J. Morikw, T. Hshimoto, E. Hykw, H. Uemur, Two-dimensionl therml nlysis for freezing of plnt nd niml cells y high-speed microscopic IR cmer, SPIE, 507 (00) [] J. Morikw, T. Hshimoto, K.Ymmoto, J. Ando, Tow-dimensionl therml nlysis for freezing of endothelil cells y high-speed microscopic IR focl plne rrys, SPIE, 5697 (007) [4] J. Morikw, T.Hshimoto, E. Hykw, T. Eto, Two-dimensionl therml nlysis of orgnic mterils y IR thermogrphy, QIRT Congress, Pdov, 006. [5] N. Miymoto, J. Morikw, T. Hshimoto, Therml diffusivity of Binry mixture of n-tricosne nd n- tetrcosne y Fourier Trnsform Temperture Wve Anlysis, Thermochim. Act 4 (005) [6] J. Morikw, T. Hshimoto, Simultneous mesurement of het cpcity nd therml diffusivity in solid-solid nd solid-liquid phse trnsitions of n-lkne, Thermochim. Act, 5-5, (000) [7] C. Prdere, M.Jonicot, J.C. Btsle, J. Toutin, C. Gourdon, Processing of temperture field in chemicl microrectors wuth infrred thermogrphy, QIRT J. Vol. No. (006) 7-5.

a * a (2,1) 1,1 0,1 1,1 2,1 hkl 1,0 1,0 2,0 O 2,1 0,1 1,1 0,2 1,2 2,2

a * a (2,1) 1,1 0,1 1,1 2,1 hkl 1,0 1,0 2,0 O 2,1 0,1 1,1 0,2 1,2 2,2 18 34.3 The Reciprocl Lttice The inverse of the intersections of plne with the unit cell xes is used to find the Miller indices of the plne. The inverse of the d-spcing etween plnes ppers in expressions