Microporous and Mesoporous Materials

Transcription

1 Miroporous nd Mesoporous Mterils 115 (28) Contents lists ville t SieneDiret Miroporous nd Mesoporous Mterils journl homepge: The effet of tioni surftnt nd some orgni/inorgni dditives on the morphology of mesostrutured sili templted y pluronis Altug S. Poyrz, Ceml Alyrk, Ömer Dg * Lortory for Advned Funtionl Mterils, Deprtment of Chemistry nd Institute of Mterils Siene nd Nnotehnology-UNAM, Bilkent University, 68 Ankr, Turkey rtile info strt Artile history: Reeived 7 Jnury 28 Reeived in revised form 25 Ferury 28 Aepted 26 Ferury 28 Aville online 4 Mrh 28 Keywords: Mesoporous sili Spheres Wormlike prtiles Ctioni pluroni intertions Morphology Tri-lok opolymers (poly(ethylene oxide) poly(propylene oxide) poly(ethylene oxide), represented s EO x PO y EO x ), pluronis (F127 = EO 16 PO 7 EO 16, P65 = EO 2 PO 3 EO 2, P85 = EO 27 PO 39 EO 27, P13 = EO 17 PO 55 EO 17, nd P123 = EO 2 PO 7 EO 2 ) nd tioni surftnts (ethyltrimethylmmonium romide (CTAB)), two surftnt systems, form omplex mielles tht self-ssemle into mesostrutured prtiles with distint morphology depending on the pluroni type, the onentrtion of the tioni surftnt nd the orgni inorgni ingredients in silieous retion medi under idi onditions. The CTAB P65 nd CTAB P85 systems form spheres, CTAB P13 nd CTAB P123 systems form wormlike prtiles, nd CTAB F127 system form single rystls of mesostrutured sili prtiles under very similr onditions. However ddition of vrious slts (suh s KCl nd NNO 3 ) into CTAB P13 or CTAB P123 solution system nd ylohexne nd KCl into CTAB P85 solution system produes the mesostrutured sili spheres nd wormlike prtiles, respetively. By ontrolling the hydrophili hydrophoi hrter of the pluronis, ore oron interfe, y mens of dditives, suh s smll orgni moleules or slts, one ould otin the desired morphology tht is ditted y the shpe of the mielles of the pluroni tioni surftnt omplex. The effets of the dditives nd the formtion mehnism of those morphologies hve een disussed using spetrosopy (FT-IR nd Rmn), diffrtion (XRD) nd mirosopy (POM nd SEM) dt. Ó 28 Elsevier In. All rights reserved. 1. Introdution Sine the disovery of mesoporous sili [1,2], there hs een tremendous effort devoted to funtionlizing the mesoporous mterils either y surfe modifition using vrious tive hemils or y ontrolling their morphology. Mny reserh groups hve synthesized spheril mesoporous sili [3 1] in ll sizes for vrious purposes, from drug delivery systems to photoni rystls. Yno et l. [3] hve estlished method of mking nnospheres with uniform size distriution using tioni surftnt in wter/methnol solution in si medi. Mes et l. [8] hve used pluronis, P123 nd F127, to produe spheril eds using tioni surftnt s o-surftnt. However, in the tioni surftnt/pluroni systems, it is diffiult to otin uniform size distriution [8 1] nd yet the role of the tioni surftnt is not lrified. Ozin et l. [11,12] investigted surftnt sili hemistry tht yields vrious shpes inluding gyroids, ropes, toroids, disoids, shells, knots et. Mny groups hve ltter estlished methods to synthesize one shpe in one pot [3 1,13 16]. Tng et l. * Corresponding uthor. Tel.: ; fx: E-mil ddress: dg@fen.ilkent.edu.tr (Ö. Dg). [13] hve systemtilly investigted the topologil trnsformtion of mesostrutured sili from gyroids to spheres using three surftnt systems, tioni (CTAB), nioni (Sodium Dodeyl Sulphte, SDS) nd non-ioni (P123) nd o-surftnt (ethylette, EA). Three surftnt systems, CTAB SDS P123 nd CTAB SDS P123 EA hve een used to mke spheres, ropes, nd helil mesostrutured sili mterils [13,14]. Yng et l. [15] investigted similr trnsformtion of rod-like to vesile-like mesoporous sili y inresing the hydrophoi ontent of the medi in triisopropylenzene-p123 system. Stuky et l. [17] investigted the formtion of single rystls nd ropes from P18 nd P123 systems, respetively, using vrious slts. Synthesizing single shpe in one pot is importnt for mny pplitions, suh s tlysis, dsorption, seprtion, sensors nd s host for CVD for vrious purposes (opti, mgneti, photoni et.). There re mny efforts towrds ontrolling the morphology [3 1,16,17]. Controlling the slt type nd the slt onentrtion influenes oth the morphology [16] nd struture of the mesophses [18 2]. The presene of slt ions, espeilly the nions, influenes the hydrophiliity of the pluronis oth in liquid nd liquid rystlline medi [18 2]. We hve investigted how the nitrte nd perhlorte ions hnge the hyrophili hydrophoi lne of the pluronis during the synthesis of mesostrutured sili films /$ - see front mtter Ó 28 Elsevier In. All rights reserved. doi:1.116/j.miromeso

2 A.S. Poyrz et l. / Miroporous nd Mesoporous Mterils 115 (28) nd monoliths [18]. Other thn few studies, [13 15] the urrent literture minly fous on finding retion onditions to produe one shpe or to otin uniform prtile size distriution in one pot synthesis. In this ontriution, we hve synthesized mesostrutured sili spheres, wormlike prtiles nd single rystls using P65, P85, P13, P123 nd F127 with CTAB s o-surftnt in n idi medi. Most of these smples hve een synthesized for the first time, nd investigted the role of CTAB moleules nd some dditives (suh s slts nd ylohexne) using PXRD, SEM, EDS, FTIR nd Rmn spetrosopy tehniques Chrteriztion The powder X-Ry diffrtion (PXRD) ptterns were olleted on Rigku Miniflex diffrtometer using high power Cu K soure operting t 3 kv/15 ma. The XRD ptterns of the smples were olleted in the 1 1, 2h rnge with sn rte of 2. Experimentl setion 2.1. Synthesis The proedure estlished y Mes et l. [8] or its modified version hve een used for the synthesis of mesoporous sili with different morphologies. By using similr proedure mesostrutured sili spheres, wormlike prtiles nd single rystls were synthesized using P85, P65, P123, P13, nd F127 tri-lok opolymers with tioni surftnt (CTAB). In typil synthesis proedure,.123 g of etyhltrimethylmmonium romide (CTAB) ws dissolved in.14 M 5 ml HCl solution y ontinuous stirring. To this solution,.62 g of P85 (EO 27 PO 33 EO 27 ) ws dded nd slowly heted while stirring to otin ler solution. The experiments ontining dditionl ingredients were onduted y following the sme proedure. In these experiments vrious slts (KCl or NNO 3 ) nd orgni moleules (ylohexne) were dded nd ompletely dissolved efore the ddition of pluroni surftnt. Then the ler solution ws ooled to room temperture (RT) nd then 1.25 g tetrmethylorthosilite (TMOS) ws dded y vigorous stirring. The finl solution ws stirred for nother 3 min t RT nd then kept in n oven t 95 C for 5 dys. The preipitte otined from the ove mixture ws filtered, wshed with exess wter nd kept in n oven t 6 C to dry. Other ompositions, hnges in the CTAB/pluroni mole rtios, the mount of dded slts nd orgni moleules hve een desried in the results nd disussion setion nd tulted in Tle 1. Tle 1 The type of pluronis, pluroni/id/tmos mounts, CTAB/Pluroni mole rtio, dditive onentrtion used in the proedure given in the experimentl setion nd the oserved morphologies Pluronis CTAB/Pluroni (mole rtio) Additives Morphology P Sphere P85. Disordered.18 Wormlike.61 Wormlike nd sphere 1.22 Sphere Sphere nd films 1. Monoliths ml Wormlike Cylohexne g KCl Wormlike g NNO 3 Sphere P Wormlike P Wormlike F Disordered 2.5 Rhomododehedron (mjor prtiles) Aove 5. Rhomododehedron (only produt) The pluroni (grms)/id (molrity, ml)/tmos (grm) mounts re.62/.14 M, 5 ml/1.23 in ll smples. Fig. 1. The SEM imges of mesostrutured sili prtiles synthesized using () CTAB P85 (CTAB/P85 mole rtio of 2.5), () CTAB P13 (CTAB/P13 mole rtio of 3.), nd () CTAB F127 (CTAB/F127 mole rtio of 5.).

3 55 A.S. Poyrz et l. / Miroporous nd Mesoporous Mterils 115 (28) /min. The polrized optil mirosopy (POM) imges were reorded in trnsmittne mode on Meije tehno ML 94 series Polrizing Mirosope with trnsmitted light illumintion, using onvergent white light etween prllel nd ross polrizers. The FTIR spetr were reorded using Bruker Tensor 27 model FTIR spetrometer. A DigiTetTM DLATGS detetor ws used with resolution of 4 m 1 nd 256 sns in the 4 4 m 1 rnge for ll smples. The miro-rmn spetr were reorded on LRm onfol Rmn mirosope with 3 mm fol length. The spetrometer is equipped with HeNe lser operted t 2 mw, polrized 5:1 with wvelength of nm, nd element CCD mer. The snning eletron mirosopy (SEM) imges of ll smples were reorded on ZEISS EVO4. The smples were prepred y dispersing the powders onto luminum holders using etone. Energy dispersive X-Ry sttering (EDS) mps were olleted using the sme SEM using Bruker AXS XFlsh detetor Results nd disussion We hve pplied modified version of the methods estlished y Mes et l. [8] in the CTAB Pluroni systems to synthesize mesostrutured sili prtiles. In this investigtion, five different pluronis, P65, P85, P13, P123, nd F127 hve een used with CTAB s o-surftnt. The CTAB/Pluroni mole rtio ws vried from. to 1. to optimize the retion onditions nd to eluidte the effet of CTAB in the formtion of the mesostrutured sili prtiles. The s-synthesized smples fter wshing nd drying proess were hrterized y mirosopy, spetrosopy nd diffrtion methods. Fig. 1 disply the SEM imges of the s-synthesized mterils. The imges lerly show tht the prtiles re spheril in se of the CTAB P65 (not shown) nd CTAB P85 systems, wormlike in the se of CTAB P13 nd CTAB P123 (not shown) systems nd single rystlline in the CTAB F127 system in idi medi under our retion onditions, Fig. 1. The wormlike morphologies from (1) (1) (11) CTAB-P85 CTAB-P (2) (21) (22) CTAB-P13 hkl d-sping (A) (1) 89.9 (11) 51.8 (2) 45. (21) 34.3 (22) 25.6 (44) 12.9 (44) e (211) d 8 4 (1) (11) (2) (11) (2) (21) (31) 8 4 (222) (321) (411) (422) Fig. 2. The PXRD ptterns of the mesostrutured sili otined from system of () CTAB P65 (CTAB/P65 mole rtio of 3.), () CTAB P85 (CTAB/P85 mole rtio of 2.5), () CTAB P13 (CTAB/P13 mole rtio of 3.3), (d) CTAB P123 (CTAB/P123 mole rtio of 2.) nd (e) CTAB F127 (CTAB/F127 mole rtio of 6.).

4 A.S. Poyrz et l. / Miroporous nd Mesoporous Mterils 115 (28) CTAB P85 system or spheril morphology from CTAB P123 n lso e otined upon the ddition of n dditive to the retion medi (see text ltter). This ontrol ws hieved either y dding non-polr ingredients or lkline metl slts. Eh shpe n e otined from CTAB Pluroni ouple in rod rnge of CTAB/Pluroni mole rtios. Fig. 2 shows the PXRD ptterns of vrious smples prepred using five different pluronis in the presene of vrious mounts Fig. 3. The SEM imges of the mesostrutured sili otined from CTAB P85 systems with CTAB/P85 mole rtio of ()., ().18, ().61, (d) 1.22 nd (e) 2.5 nd of CTAB F127 with CTAB/F127 mole rtio of (f) 1.67, (g) 3.33, nd (h) 5..

5 552 A.S. Poyrz et l. / Miroporous nd Mesoporous Mterils 115 (28) of CTAB. The use of P65, P85, P13, nd P123 enles us to tune the unit ell dimeters in the spheres in rod rnge, from 6 to 1 nm. The CTAB P65 or CTAB P85 systems nd the CTAB P13 or CTAB P123 systems produe 2D hexgonl mesostrutures with P6mm spe group with either spheril or wormlike morphologies, respetively. However, only the wormlike strutures re irefringent under POM etween the rossed polrizers, inditing tht the hnnels re oriented long the rope xis rther thn rndom s in the spheres. The smples otined from the CTAB P13 system disply up to six diffrtion lines, whih n e indexed to (1), (11), (2), (21), (22), nd (44) plnes of 2D hexgonl struture with P6mm spe group, Fig. 2. The mesostrutured CTAB F127 smples hve rystlline morphology with rhomododehedron shpe. The XRD pttern of the rystlline smple hs diffrtion lines t 2.4, 1.76, 1.56, 1.44, 1.2 o,2h orresponding to (422), (411), (321), (222), nd (211) refletions of Im3m spe group of ui symmetry with unit ell prmeter of equls to 21.2 nm. Note lso tht the smples prepred without CTAB do not diffrt t smll ngles, inditing tht the mesostruture is disordered or does not form in the sene of CTAB under our retion onditions. The effet of CTAB to the CTAB P85 nd CTAB F127 systems hs een investigted y rrying out the following experiments. The tioni surftnt to pluroni mole rtio ws vried from. to 6.6 in the CTAB P85 nd. to 1. in CTAB F127. In the sene of the tioni surftnt, one gets ggregted smll prtiles with distint ut not well defined morphology, Fig. 3. In the presene of enough CTAB, t lower CTAB onentrtions, the prtiles re only wormlike (CTAB/P85 mole rtio of.1.6), spheril t intermedite onentrtions (CTAB/P85 mole rtio of.8 4.) nd mixture of films nd spheres t high onentrtions (CTAB/P85 mole rtio of ), Fig. 3. The ddition of smll mount of CTAB prevents ggregtion of the prtiles inditing tht the CTA + ions re lso on the surfe of the growing prtiles. The CTA + ions form omplex t intermedite onentrtions (CTAB/ P85 mole rtio of.8 2.5) nd the exess CTA + ions go to the ir wter interfe to produe mesostrutured sili films, Fig. 3e. Note tht the smples prepred using high CTAB onentrtions ontin lrge mount of film smples, formed in the ir wter interfe. Those film smples diffrt t smll ngles hrteristi of film smples prepred using pure CTAB. If one prepres Intensity Differene (ps) m m m m Wvenumer (m -1 ) Fig. 4. Miro-Rmn differene spetr etween mesostrutured sili otined from CTAB P85 systems nd pure P85 (CTAB/P85 =., X) () the CTAB/P85 mole rtios of.46 X, () CTAB/P85 mole rtios of 1.66 X, nd () CTAB/P85 mole rtios of 3.33 X. with even lrger quntities of CTAB, one otins monoliths t the ottom of the retion vessel. Therefore, we did not further investigte those smples. Fig. 4 displys the Rmn differene spetr of the sili spheres otined from the CTAB P85 (CTAB/P85 mole rtio of.46, 1.66 nd 3.33) system nd sili prtiles otined from pure P85 system under similr retion onditions. Notie tht the peks mrked on the differene spetr t 2852 m 1 orrespond to the dissolved CTAB (see lter) nd ll the other peks t 2881, 294 nd 2978 m 1 orrespond to symmetri t-ch 2, symmetri nd symmetri t-ch 3 groups of the PO units [21], respetively. The spetrl hnges re in the PO lok of the P85 moleules nd the dissolved CTAB signls eome visile in the differene spetr, whih suggests tht the CTA + ions intert with the PO units of the P85 moleules nd re involved in the ssemly proess. Most likely, the intertion of the lkyl til of the CTAB moleules within the PO ore of the CTAB P85 mielles influenes the onformtion on the PO loks nd s result lters the intensity of the CH 2 nd CH 3 groups of the PO units. We hve further investigted the CTAB P85 system in vrious onditions to disover the intertions etween the CTAB nd P85 nd lso to determine the funtions of the CTA + ions in the mesostrutured sili ssemly proess. The spetrl hnges, shown in Fig. 4 nd the oserved morphology, shown in Fig. 3 e, re onsistent with eh other suh tht, the differene spetr disply lmost no hnge ove 3.33 CTAB/P85 mole rtios, inditing tht the exess CTAB moleules re not prt of the mesostrutured sili. Moreover, in the CTAB F127 systems, one needs more tioni surftnt to oserve the effet. The single rystls form t CTAB/F127 mole rtio s low s 3.33, ut the pure rystls form t higher onentrtions, CTAB/F127 mole rtio of 5. nd ove, Fig. 3f 5h. The CTAB P123 nd CTAB P13 systems usully produe wormlike morphology in rod rnge of CTAB onentrtions. However t higher CTAB/Pluroni rtios, the spheril prtiles n lso e otined from the CTAB P123 (CTAB/P123 mole rtio of 5.) nd CTAB P13 (CTAB/P13 mole rtio of 3.3) systems. The spheril morphology is usully otined t reltively lower CATB/Pluroni mole rtios in smller pluronis, suh s P65 versus P85 nd P13 versus P123. The CTAB P85 system lso produe wormlike prtiles if the CTAB/P85 mole rtio is elow.5, however the CTAB P65 system gives spheril prtiles t mole rtio s low s.1. Similrly, the CTAB/P13 gives only spheril prtiles, if the CTAB/P13 mole rtio is higher thn 2.5. However, the spheril nd wormlike prtiles with muh smller spet rtio oexist in the CTAB P123 system with CTAB/P123 mole rtio s high s In ll CTAB Pluroni systems, the CTA + ions influene the hydrophiliity of the pluronis y inorporting the lkyl til of the tioni surftnt into the polypropylene oxide ore nd rrying the negtively hrged ounter nions together to the polypropylene oxide polyethylene oxide region of the pluronis. This mkes the PPO PEO interfe more hydrophili, see Sheme 1. Notie tht the PEO/PPO mole rtio is higher, 1.64 nd 1.33, in oth P65 nd P85, respetively, thn tht of.62 nd.57 in P13 nd P123, respetively. Therefore in oth P65 nd P85 systems, the medi is hydrophili enough, suh tht there is no need for lrge mounts of tioni surftnt to produe spheril prtiles. However, F127 is even more hydrophili thn P65 nd P85, still one needs high CTAB onentrtions in the CTAB F127 system, therefore the size to hrge rtio of the CTAB Pluroni mielle omplex is lso s importnt. The intertion nd formtion of omplex etween tioni surftnt nd pluronis, were further investigted using Rmn nd FTIR spetrosopy methods. Fig. 5 nd disply series of Rmn spetr of wter CTAB, wter P85, nd wter CTAB P85 systems in vrious stges of the wter evportion. Notie tht

6 A.S. Poyrz et l. / Miroporous nd Mesoporous Mterils 115 (28) m m e d 2852 m Wvenumer (m -1 ) Wvenumer (m -1 ) 28 d 2852 m * 14 Asorne (.u.) Wvenumer (m -1 ) Wvenumer (m -1 ) Fig. 5. The Rmn spetr of (A) wter CTAB mixture with wter evportion; through, (B) () pure P85, () 1% w/v P85 + H 2 O mixture, () mesostrutured sili synthesized using P85 s struture direting gent, (d) mixture of 1% w/v CTAB + P85 + H 2 O, nd (e) mesostrutured sili synthesized from CTAB P85 system nd (C) miro- Rmn nd (D) FTIR spetr of mesostrutured () CTAB P65 SiO 2, () KCl CTAB P65 SiO 2 nd () NNO 3 CTAB P65 SiO 2. the spetr of the wter CTAB hnges drstilly upon evportion of wter, Fig. 5. The pek t round 2886 m 1 tht origintes from the symmetri strething mode of CH 2 groups of CTA + ion is very sensitive to dissolution. The spetrum of the CTAB P85 omplex (see Sheme 1) in the presene of smll mount of wter losely resemles tht of the spetrum of the mesoporous sili mterils prepred using CTAB nd P85, inditing tht oth surftnts re present in the hnnels. Note lso tht the spetrum of the dissolved P85 is quite different from the spetr tht ontin CTAB nd P85 mixtures. The pek t 2852 m 1 ppers only in the presene of CTAB in ll spetr (the spetr of CTAB P85 H 2 O, CTAB P85 SiO 2 nd CTAB P85 [Zn(H 2 O) 6 ](NO 3 ) 2 mixtures) without the intense symmetri strething mode of the CH 2 units of CTAB rystls t round 2885 m 1, inditing tht the CTAB is ompletely dissolved in ll ses, in form of CTAB-P85 omplex. The FTIR spetr of the mesoporous sili prepred using P85 in the presene nd sene of CTAB re lso presented in Fig. 5 for omprison purpose. Notie tht these two spetr differ slightly from one nother. The differene spetrum of the two spetr shows pek relted to the dissolved CTAB. Bsed on our IR nd Rmn oservtions we suggest tht the CTAB P85 omplex in the mielle form efore intertion with the sili speies in the selfssemly proess. The omplexing of CTAB Pluronis mkes the mielles positively hrged, thus enhnes the surftnt sili ssemly proess. As disussed ove, the CTAB moleules ply importnt roles in the sili ssemly proess. The formtion of omplex etween the CTA + ions nd pluroni provides positive hrges to eh mielle, Sheme 1. Therefore, the unit ell prmeters of the prtiles re determined y the size of the pluroni mielles, Fig. 2. The omplex formtion hs een investigted using FTIR nd Rmn spetrosopy tehniques in this work using s-synthesized

7 554 A.S. Poyrz et l. / Miroporous nd Mesoporous Mterils 115 (28) Sheme 1. mesostrutured sili prtiles, wter CTAB, wter CTAB P85, nd CTAB P85 [Zn(H 2 O) 6 ](NO 3 ). Note lso tht the CTAB P85 [Zn(H 2 O) 6 ](NO 3 ) mixture form liquid rystlline mesophses tht losely resemles the struture of mesostrutured sili, CTAB P85 SiO 2. Note tht the intertion of surftnts (non-ioni, tioni nd nioni) with pluronis hs een widely investigted in queous solutions nd in liquid rystlline phses using light sttering, lorimetry, smll-ngle X-ry sttering nd NMR tehniques [22 26]. It is ommon onlusion tht the tioni surftnt moleules intert with pluronis to form hrged omplex mielles in n queous medi [22 24], whih is onsistent with our proposl. It is known tht the presene of nions lso influenes the onformtion, s result the hydrophiliity, of the ethylene oxide groups of the pluronis [27 29]. The nions of metl slts influene the soluility, onformtion of the surftnts in oth liquid nd liquid rystlline medi [27 29]. It hs lso een shown tht the nions of the slts hve gret effet on the morphology of the mesostrutured sili in dilute nd onentrted medi [14,16,3]. Some nions, on the left hnd side of the Hofmeister s series [31] ðso 2 4 > HPO 2 4 > CrO 4 > CO2 3 > Cl Þ, re known to e lyotropi nd mke the surftnt moleules more hydrophoi, nd the others, on the right hnd side of the series ðbr > NO 3 > I > ClO 4 > SCN Þ, re known to e hydrotropi nd mke the surftnt moleules more hydrophili [27 29]. We hve further investigted the role of hydrophili hydrophoi lne in the PPO ore nd PEO oron interfe y other dditives. For this purpose, the effet of two different nions, Cl (lyotropi) nd NO 3 (hydrotropi) nd ylohexne s hydrophoi dditive hve een tested in our retion onditions. The ddition of KCl or ylohexne to the CTAB P85 system, even t 2.5 CTAB/P85 produes wormlike morphology, Fig. 6 nd. Note tht oth Cl nd ylohexne mke the P85 mielles more hydrophoi. The Cl ions oupy the hydrophili regions of P85 omplex mielles nd enhne the ontriution of the PPO lok of P85, similrly ylohexne moleules go to the PPO region of the mielles nd enhne the hydrophoi intertions. However, in the presene of NNO 3, one gets spheril morphology, Fig. 6. The FTIR nd Rmn spetr of the three smples prepred using CTAB P65 system nd presene of hloride nd nitrte slts re displyed in Fig. 5 nd d. The mount of dissolved CTAB moleules (differene spetr etween the smples with nd without slts disply spetrum similr to dissolved CTAB) in the mesostrutured sili is enhned in the presene of oth Cl nd NO 3 nions, Fig. 5 nd d. However, the mount of dissolved CTAB is notiely higher in the nitrte se. The lyotropi nions oupy the qu medi lose to the EO til; however, the hydrotropi nions oupy the ethylene oxide propylene oxide interfe mking the medi more hydrophili, see Sheme 1. Shs et l. [32] hve studied the dynmis of nion penetrtion into the hydrophoi domins of lipids where the hydrotropi nions penetrte further, therey disrupting the hydroron pking. Shs et l. s finding is onsistent with our oservtions nd model. The ddition of slts of the lyotropi nions hve n effet similr to inresing the PO units of the pluronis, enhning the hydrophoiity of the medi or the hydrophoi intertions, see Sheme 1. Similrly, the ddition of slts of hydrotropi nions mkes the pluronis more hydrophili nd hs the effet of inresing the EO units. The distriution of the nions in the EO units from the PO ore towrds EO oron influenes the onformtion on the EO units in the pluronis, s result the effetiveness of the ethylene oxide groups. The distriution of the nions lso ffets the hydrting (hydrotropi ions wet) nd dehydrting (lyotropi ions dry) of the PO units nd, s result, the onformtion in the PO ore nd EO oron of the mielles.

8 A.S. Poyrz et l. / Miroporous nd Mesoporous Mterils 115 (28) spheres nd wormlike prtiles re 2D hexgonl while the single rystls re ui. The ddition of tioni surftnt influenes the hydrophili hydrophoi hrter of the pluronis nd ffets the morphology. The tioni surftnt pluroni intertion mkes the pluronis more hydrophili nd provides positive hrge to their mielles, whih influenes the ssemly of the sili speies. The mount of the tioni surftnt required for one type of morphology is low in the smller pluronis, t CTAB/P65 mole rtio s low s.1 in the CTAB P65 system, nd lrge in the lrger pluronis, t CTAB/F127 mole rtio s high s 5., in the CTAB F127 system. Most likely some tioni surftnt moleules remin in the solution nd modify the surfe of the growing sili prtiles. The ddition of lyotropi nions, suh s Cl nd non-polr orgni moleules mkes the pluroni mielles more hydrophoi suh tht the effet is equivlent to deresing the ethylene oxide units in the pluronis. One n otin ll three morphologies y influening the hydrophili hrter of the pluronis using slts or orgni ompounds in the retion medi. Further studies re required to expnd the onept using other pluronis, oligo(ethylene oxide) type nonioni surftnts nd my e nioni surftnt insted of tioni surftnt. Aknowledgments ÖD grtefully knowledges the Sientifi nd Tehnil Reserh Counil of Turkey (TÜB _ ITAK) in the frmework of the projets 15T224 nd 15M96 nd Turkish Ademy of Siene for the finnil supports. Referenes Fig. 6. The SEM imges of mesostrutured sili otined from CTAB P85 system with CTAB/P85 mole rtio of 2.5 in the presene of () 1 g KCl, () 5 ml Cylohexne, nd () 1 g NNO Conlusion Three different morphologies were investigted under similr retion ondition in CTA Pluroni Sili system, nmely spheres, wormlike prtiles nd single rystls. Inresing the ethylene oxide units in the pluronis hnges the morphology from wormlike prtiles to spheril prtiles nd to single rystls in the presene of tioni surftnt. The mesostrutures in the [1] T. Yngisw, T. Shimizu, K. Kurod, C. Kto, Bull. Chem. So. Jpn. 63 (199) 988. [2] C.T. Kresge, M.E. Leonowiz, W.J. Roth, J.C. Vrtuli, J.S. Bek, Nture 359 (1992) 71. [3] K. Yno, Y. Fukushim, J. Mter. Chem. 13 (23) [4] Y. Ymd, T. Nkmur, M. Ishi, K. Yno, Lngmuir 22 (26) [5] M. Mizutni, Y. Ymd, K. Yno, Chem. Commun. 11 (27) [6] L. Qi, J. M, H. Cheng, Z. Zho, Chem. Mter. 1 (1998) [7] R.I. Nooney, D. Thirunvukkrsu, Y. Chen, R. Josephs, A.E. Ostfin, Chem. Mter 14 (22) [8] M. Mes, L. Sierr, B. Lopez, A. Rmirez, J.L. Guth, Solid Stte Si. 5 (23) 133. [9] J.P. Hnrhn, A. Donovn, M.A. Morris, J.D. Holmes, J. Mter. Chem. 17 (27) [1] W.J.J. Stevens, K. Leeu, M. Mertens, G.V. Tendeloo, P. Cool, E.F. Vnsnt, J. Phys. Chem. B 11 (26) [11] H. Yng, N. Cooms, G.A. Ozin, Nture 386 (1997) 692. [12] H. Yng, G.A. Ozin, C.T. Kresge, Adv. Mter. 1 (1998) 883. [13] B. Wng, W. Shn, Y. Zhng, J. Xi, W. Yng, Z. Go, Y. Tng, Adv. Mter. 17 (25) 578. [14] B. Wng, C. Chi, W. Shn, Y. Zhng, N. Ren, W. Yng, Y. Tng, Angew. Chem. Int. Ed. 45 (26) 288. [15] G. Zhou, Y. Chen, J. Yng, S. Yng, J. Mter. Chem. 17 (27) [16] J. Wng, J. Zhng, B.Y. Asoo, G.D. Stuky, J. Am. Chem. So. 125 (23) [17] C. Yu, B. Tin, J. Fn, G.D. Stuky, D. Zho, J. Am. Chem. So. 124 (22) [18] A.F. Demirörs, M. Arsln, Ö. Dg, Miropor. Mesopor. Mter. 98 (27) 249. [19] A.F. Demirörs, B.E. Eser, Ö. Dg, Lngmuir 21 (25) [2] C. Alyrk, G. Gülten, Ö. Dg, Lngmuir 23 (27) 855. [21] C. Guo, J. Wng, H.Z. Liu, J.Y. Chen, Lngmuir 15 (1999) 273. [22] Y. Li, R. Xu, S. Couder, D.M. Bloor, J.F. Holzwrth, E. Wyn-Jones, Lngmuir 17 (21) [23] J. Jnsson, K. Shillen, G. Olofsson, R.C. d Silv, W. Loh, J. Phys. Chem. B 18 (24) 82. [24] J. Jnsson, K. Shillen, M. Nilsson, O. Södermn, G. Fritz, A. Bergmnn, O. Gltter, J. Phys. Chem. B 19 (25) 773. [25] D. Löf, A. Niemie, K. Shillen, W. Loh, G. Olofsson, J. Phys. Chem. B 111 (27) [26] K. Armki, Md.K. Hossin, C. Rodriguez, M.H. Uddin, H. Kunied, Mromoleules 36 (23) [27] H. Shott, J. Colloid Interfe Si. 192 (1997) 458. [28] T. Iwng, M. Suzuki, H. Kunied, Lngmuir 14 (1998) [29] C. Rodriguez, H. Kunied, Lngmuir 16 (2) [3] E. Leontidis, Curr. Opin. Colloid Interfe Si. 7 (22) 81. [31] F. Hofmeister, Arh. Exp. Pthol. Prmokol. 24 (1888) 247. [32] J.N. Shs, T.B. Woolf, J. Am. Chem. So. 125 (23) 8742.