Mesoporous Materials Amorphous, disordered - silica xerogels Ordered, amorphous walls Pore diameter, d [nm] Material Example 1 d>50 Macroporous Aerogels 2 , in Mi 4H 100 Ertl íl] IJjQI "id ib ao ä so Dggraoa 2-ttrota Silica Shoots 5 Supramolecular Templating Surfactants - amphiphilic molecules, polar (head group)and nonpolar (chain, tail) part lyophilic, lyophobic Ionic surfactants, cationic, anionic, zwitterionic Nonionic amines, polyethyleneoxides A - normal surfactant molecule B - gemini C - swallow tail ABC 6 n a Surfactants Hydrolrope (llexibla Surfactant) Bolalorm surfact&rrt l Diblock copolymer surfactant Classical surfactant (ngid suriactsrtl) Gemini surfactant fdime*ie) Polymeric surfactant 7 Surfactants Anionic • sulfates: • sulfonates: • phosphates: carboxylates: Cationic • alkylammonium salts: dialkylammonium salts: CnH2n+1OS03 Na+ C„H2n+1S03H C„H2n+1OP03H2 CnH2n+1COOH CnH2n+1(CH3)3NX X = OH, CI, Br, HS04 (C16H33)2(CH3)2N+Br Noionic • primary amines: • polyethyleneoxides: C„H2n+1NH2 HO(CH2CH20)nH 8 Supramolecular templatíng 280 H J___i.....I......,»,J„ . I—i—i—í—L X—,__L C*fCl CMC2 T—'—1—"—|—■—I—'—I—'—1—'-----1-----'-----1-----" 0 10 20 30 40 50 60 70 80 90 100 Phase diagram of C16TMABr CMC = critical micelle cone. koncentrace (hm.%) Micelles - Supramolecular Templates ; «p&i .^^h spherical >i ■a 1 I CMC2 Kod Micelle 10 Micellar shapes A -spherical, B - rod-like, C - lamellar Micelles in media A - normal, in polar solvent, H20 B - inverse, in nonpolar solvent, organics ~*—# Micellar shapes Micellar structures A ) sphere, B ) cylinder, C ) planar bilayer, D ) reverse micelles, E ) bicontinuous phase, F ) liposomes). Critical packing parameter - CPP CPP = VH/a0lc VH volume of the hydrophobic part, a0 surface area of the hydrophilic part, lc critical chain length: lc < 1.5 + 1.265 n [Á] n number of carbon atoms. lc depends on the chain shape. Head group area a volume V alkyl chain 13 CPP Surfactant < 0.33 linear chain, large head 0.33 - 0.5 linear chain, small head 0.5 -1.0 two chains, large head micelle shape spherical cylindrical bilayers Surfactant Molecules Conical {icecream cone, A) Inverse conical {champagne cork, B) 15 Surfactant Molecules -14 nm 6-10 nm micelle 4-5 nm [ i inverse cubic phase(G) -7 nm L-». -L h '. ■. i- h ^ l laniell^r inverse hexagonal pnete high low waler content 16 A. Lx= micellar solution; Nc = nematic phase; Hj = normal hexagonal phase (MCM-41; SBA-15); Vj = normal bicontinuous cubic phase (MCM-48); La = lamellar phase (MCM-50) path A, the micellar solution route path B, the lamellar phase route path C, the nematic phase route 17 Mechanism of the mesoporous material formation (hexagonal, MCM-41) LCT Liquid Crystal Templating mesostructured material ___ micellar rod surfactant micelle _____ta- M ■wffc 4jny °% V' V ■* ů--^;^-o r jfafrL/ * j^OaJfi^^pr^ lyfl^H^y 1 ľ lír inorganic presursor "H-Lu^^HL* ' '■J^^t'il V mesoporous material surfactant removal 18 General Liquid Crystal Templating (LCT) Mechanism y- o *» x SLLTfacLuil miccLEcs •+-+■ nK>]tíCLi]cs ■<}*** A,' i[rf>rsanic macular spirits aia ^x" "m. ° ° b? IfiMfJÍI d) 19 SLC Silicatropic Liquid Crystals precursor solutions £#£* />*** o tf * a * c i o- micelles and isolated cationic inorganic silicate anions surfactant molecules (for example, D4R oligomers) SLC assembly ■l§S®iäfí&transÍ0 rmation íameílar SLC Hexagonal SLC recti rsor Solutions 1^ =CTA+ 0=Br (S Ion Exchange © Assembly of the SI Ilea tropic Liquid Crystal Me&opha&e Phase Transitions 21 Lamellar to Hexagonal Transformation oil »Ante On^DlJm r HCM4lqtfi Silicate Rod Assembly 23 • Electrostatic interactions a) si Ie# b) SI+ c) SXI+ ie£- ŕW I = silicate S = trimethylammonium I = Fe2+,Fe3+,Co2+,Ni2+, Mg2+, Mn2+, Pb2+, Al S = sulfonane I = silicate - polyelectrolyte positive charge X = C1 S = trimethylammonium d) S"M+r iW I = aluminate M = Na S = phophate • Hydrogen Bond a) S°I° oTo b) Nur 0 0 I- -N- • Covalent Bond a) S-I I----S I = silicate S = ammine I = silicate N = polyethylenoxide I = niobáte, tantalate S = ammine 25 26 T 7i-nh Chur^Ľ 4* ľ.-. ľ-. fhüir^L J Negative ť tiürfir h ISiliŕA □ ■ô l^^^^™*^^^- '7 . 1 . _L , 1 . 1 1 - 1 ■ * ■> H 4 pH 10 -----------■-------------■—W-12 xw+ «-o S^ pH >9 Strong eiKtiwuiJť fnieraciLoji Wť4tk bydrofici^boiHlHB. Interacliun MCM-41 40A .^W^^^^^tP^^^^^^ hWfc-ftJlMS^fc^^Tj-i^iH^í FJTT ^1 Ľ **r «ĺ- ■ '.I* ■_ \ *»T _-*.*'" iir.:- . +<*f .A ■■ 'tíiTl IV* ^^ Lí-t: w*..*.**^:.. ■ r.-^ ■-: VťjS-Xl ES^VI pTl. ř»»^^/^ *#rl pThiA> H i beV< ^*TS**=ď £ ^- i $3 * 1 ■ *ÍVlAv^.l,i- r*^-* ' 1 v L ^ jO^*X%-i*N l «'+\v*i *^ -^í ^7 "I -^ **" + -1 ^*.. ->* ] •1 kvv* ^^litVu.1 ^ "ti 1L^ ■ 1 Kt^ľl:? P*ř>*—J-^-THjl^t 'I HE £>! -'■ »Ä^X* * *ŕ ľí.» 5» ±1 i**^ ■ ■*^-. fc; íUiŕ \f? - <■ 3 ***%»■' fe&í£ .v 7^3 Bft^frt a .^ ^« B ^Vf«c?ľ ■■ ■■■■=■: gffifJTj ®w*'-V;, ->-ä j ^íW^ta-1* .* -.V . * ./■■> ^ Hif '.*i!í^^jiSíííiUMCdST^1^^ 100 A Prepared with Mešity lene Addition 28 TEM micrograph of hexagonal molecular sieve TEM image of the Pd-grafted mesoporous silicate material 30 Silicate Layer Puckering ■WPHHB^ 31 Charge Density Matching SÍOj c i> 32 Folding Sheets Na4' CflH2^NM«j i T ITT ■h^fa^fl [\ákĚá ■"*■■■ ■■■ a) ^^^^^ b) . ■ kane mite silicate-organic complex mesoporous material 33 XRD of hexagonal MCM-41 (1QO) 70QC eooo sooo *r looo- i 3 300 2 000 100O- i 300 250 í 200 (200) iiii i ■ i ■ ■ i|ii^i|-iii| i f i ■ | iii i | ■ ' ■ i y ■ ■ ■ ■ | Z 9 4 5 Ů r 5 9 10 2 tí(dcgrcŕsl _______________ (.£00) 'i'lfM l l|l"P I l"'|'PP'H" >| l 'l'|l l M ľ 'll ['■■ '[lli'H ■ll|""| l ■■■[' " ■!■ " ' i ! 343 C 7 B 9 10 2 n (degrees) 34 XRD of lamellar MCM-50 Z500 2ŮÚ0H e isq (QQZJ »—.....■ ■ ■! P iŕ ^ Vi ■ , (003) ■—*---------- |llj||l«|BI||||||l|----■ I I | | | I 5 6 7 2 0 -H20, -C02, -NO, Mesoporous Platinum Metal H2[PtCl6] or (NH4)2[PtCl6] C16(EO)8 Assembly of liquid crystalline phase Reductants: Fe, Zn, Hg, NH2NH2 Washed with acetone, water, HCl SEM (upper) and TEM (lower) images of mesoporous Pt metal show particles 90-500 nm in diameter and a pore diameter of 30 A and a pore wall thickness of 30 A. 50nm Surface Silanols in MCM-41 Pores < (9)L I ď" —-** 2K7 z^zz^y 41 Chemistry inside the Pores 42 43