■ ^ ^ %kA     Departement de Chimie Moleculaire
l'^Oil     et Macromoleculaire CHEMISTRY: MOLECULES TO MATERIALS
Institut Charles Gerhardt Matiaiellier CMOS
surfaces with phosphonate coupling molecules
May 12, 2016 - Czech Chemical Society Lectures
• Molecular thickness: 1-2 nm, < 1 nmol/cm2
• Control of surface and interface chemical and physical properties:
- charge, surface energy, reactivity, tribological properties...
- electronic, mechanical, thermal properties...
• Applications: sensors, lab-on-a chip, hydrophobation, lubrication, catalysis, corrosion resistance, (nano)composite materials, photovoltaics,...
Binding to the inorganic surface
Functional group Anchoring group
Anchoring groups:
• Thiols R-SH : coinage metals Au, Ft, Ag, Cu..., M-S bonds
• Silanes R-Si(OEt)3, R-SiCI3: silica, metal oxides, M-O-Si + Si-O-Si bonds
• Carboxylic acids R-C02H : metal oxides, phosphates, carbonates..., M-O-C bonds
• Phosphonic acids R-P03H2: metals, metal oxides, phosphates, carbonates,
sulfides..,    M-O-P bonds
Today
Focus on: (native) oxide surfaces and phosphonic acids
• Background:
Reactivity, comparison between silanes and phosphonic acids
• Examples:
Surface modification of "flat" substrates, nanoparticles, layered materials
Organosilane monolayers
OEt CI SjOg. Zr02, Al203, Ti02...
R-SHOEt R-Sh-CI SiC, Si3N4
OEt NCI J
, Ca10(PO^fOH).
Hydrolysis: H20 + Si-X    HX + Si-OH X = CI, OR
Heterocondensation:   M-OH + Si-OH -> Si-O-M + H20
Homocondensation: Si-OH + Si-OH -> Si-O-Si + H20
Competition heterocondensation / homocondensation: governs layer structure
MOLECULES TO MATERIALS
iCGM
Organosilane monolayers
Balance heterocondensation / homocondensation: depends on the nature of the support and water content
R
R'O-Si-OR"
l
OR'
no H20
i
R
sr0Et
6   OH OHO7 X0 OH
i    i    i    i    i i
R
EtO-Si-OEt
X
only Si-O-M, partial monolayer
OH OH OH OH OH OH
I      I     I     I   _|_I
H,0
R       R R
I I i
O-Si-O—Si-O-Si
i i        i \
O  OHO OH 0 0
	=LLI	
		
R
HOJ R /Si-
HO-SHO °^Si
0 OH OHO7 X0 OH
1 i    i   i    i i
Si-O-M + Si-O-Si dense monolayer
few Si-0-M: multilayer
Phosphonic acid monolayers
Ti, Al, Stainless steel, Mg, Ag, Ti02, Al203, Zr02, Si02... CaC03, Ca10(PO4)6(OH)2, GaAs, CdS...
R Binding to oxide surfaces: formation of P-O-M bonds
I    OH k \ ^OH
OH K
OH      OH °   i   OH OH O7  O OH
I "H20
r
r
M   M   M   M -►    M   M   M   M -►       M   M   M M
^^^^^^^^^^^^^^^^^^^^^^^^^ I
Condensation Coordination
Phosphonic acids stable in water
No need to control the water content Surface modification in water
No homocondensation
P-OH + P-OH * P-O-P + H20
easy access to monolayers
Growth of C18H37P03H2 SAMs on titanium
in situ multireflexion ATR FTIR ex situ water contact angle
Substrate: 20 nm Ti on a silicon ATR crystal 1 mM C18H37P03H2in CD3CD2OD, 15 °C
FTIR
peaks area
VasCHw		vsCH2
1 week T		
1 ^y^y		
1 h^_/		
1 min r i	i	i
3000      2900 2800 Wavenumber (cm")
Water contact angle /
12      24 36
Time / h
• No need to control the water content, simple and reproducible!
Surface Modification of TiOo Particles
Ti02   +   PhP03H2    H2Q, pH 2.5 washing 50 m2/g      22 P / nm2       3d j     >     drying >
31PMAS-NMR
PhP03H2
grafted specie^
P-O-P
i
100°C
Ti(PhP03)2
100     50       0      -50 -100 8 (ppm)
20°C, 2.8 mM: no P-O-P => monolayer 100°C, 40 mM =^>Ti(PhP03)2 phase
P^h        P^h P^h
\ .o/KQ /0/KQ /0/KQ ^
TK        T\ T\ JTi
0-p'U    0-p'U 0-p'U
\ \ \
Ph        Ph Ph P^h        P^h P^h
\ /0/KQ /0/KQ „
JTi        JTi        JTi JTi 0-p'u    0-p'u 0-p"u
\ \ \
Ph        Ph Ph
Chem. Mater. 2001, i3, 4367
iC
or
hrnu ;i»Ih Gff t*s Hond»Hf
Collaboration F. Babonneau, C. Gervais (UPMC)
170-enriched
• phosphonic acids
• model compounds
OH
OH
O'Pr
DMSON | yGPr Ph^ 0       \ xPh
_       I Ph
'PrO'
•0" I
ipr
"O'Pr
C/?em. Mater. 2003, 2008
C12H25P03H2 monolayer on TiO2(100 m2/g) 170 MAS-NMR
60% P-O-Ti 20% P=0 20% P-O-H
400
200 0
5 / ppm
R p
OH OH
-200
Ti T	"Ti
1	
xp-o
0 0
_l_l_
/^OH
O O
j_i
9 9 9
TiQ2 I
Mechanism
Surface species
Collaboration Ph. Tordjeman LAIN
Applications of SAMs:
corrosion protection non-volatile lubricants
hard-disks
MEMS
electrical contacts
C18H37P03H2 SAMs as lubricant coatings stable in alkaline media
Substrates: 20 nm Ti on Si grafting with C18H37P03H2 in EtOH, 2d.
Friction: stainless steel ball D = 2 mm, 260 HV, normal force up to 60 N
Ti/Si untreated Contact angle 11° Friction coeff. 0.6
ODPA/Ti/Si Contact angle 102° Friction coeff. 0.1
MRS Symp. Proc. 2004
Lubrication maintained after 100 min pH 14, 65 °C
ICGM
Antibacterial phosphonate monolayers
Collaboration J.-Ph. Lavigne CHU; Daniele Noel INM
Bacterial adhesion / biofilm formation: major cause of nosocomial infections
Biofilm formation
Stainless steel, Cr/Co or zirconia
HAP
TA6V, stainless steel
Inorganic biomaterials:
metals, metal oxides, phosphates.
Phosphonate monolayers as coatings for medical devices:
• high affinity for most inorganic biomaterials
• good thermal and hydrolytic stability
iCGM
Strategy: grafting of silver thiolate groups
Ag+: good bactericidal activity over a wide range of bacteria Ag thiolates: very high hydrolytic stability
OH  OH 9H OH
I I   I   I   I g
HO-^0 HO
EtOH
Titanium 48h rt Stainless steel -\ m|\/|
SH SH
o o ° o o o
_L_L
_L_L
.....I
Ti-SH
AgN03 1 mM 2h, r.t.
AgS AgS
.....E
Ti-SAg
J. Mater. Chem. 2009, 19, 141 - 1 WO 2007080291
iC
o.
Bacterial adhesion and biofilm assays:
	106n
	
E	105-
m	
	
	104-
	
o	103-
c	
	
er	102
JZ	
T3	
<	101-
J E. coli
S. epidermidis
Ti      Ti EO Ti-SAg Ti-SAg EO Sample
huge decrease of bacterial adhesion after 2-h incubation
Ti EO + S. epidermidis Ti -SAg EO+ S. epidermidis
inhibition of biofilm growth after 3-day incubation
• good antibacterial activity in vitro and in vivo with less than 1 nmol Ag/cm2
• maintained after ethylene oxide sterilization
• excellent biocompatibility in vitro (MCT3T3 cells) and in vivo
Acta Biomaterialia, 2015, 154, 266-277
iCGM
tautiil '1»ih t/ftwS Hontmi**
Dielectric / metal interfaces
Collaboration Ganpati Ramanath RPI
Tuning interface mechanical and thermal properties
Modification of the interface by a MDPA monolayer:
• interfacial toughness: x3
• thermal conductance: x3 Nature Mater-2013
iCGS
Selective surface modification
Ti-O-P : stable / hydrolysis   Si-O-P : fast hydrolysis
P12H25
TiO.
SiO.
Patterned support
H01h°
HoO
SEM
100
SAES line scan
TiO.
	m
	
0       5      10 15 Distance (urn)
Repartition of organic groups controlled by the inorganic support
Chem. Mater. 2004 16, 5670
iC
o.
collaboration Rhodia, MACS (ICGM)
Compatibilization of silica nanofillers with hydrophobic polymers
Surface modification in aqueous medium? Organotrialkoxysilanes: not stable in water
Phosphonic acids: stable in water but Si-O-P not stable in water =^> Si-O-AI-O-P
SiO;
AICU C8H17P03H2
«7AI/nm2 1-8P/nm2 30' pH 6.5     30' pH 6.5
31PMAS-NMR
4.1 P/nm2
100
50 0 5 / ppm
• fast, one-pot method
• no organic solvent: "green"
• no precipitation of Al phosphonate
• controlled surface coverage
J. Mater. Chem. 2011
iCGM    Grafting oxide NPs in aqueous colloidal solutions
collaboration J. Oberdisse, C. Genix L2C
Silica colloids: used in ceramics, composite materials, cements, catalysts,
polishing pastes, paper, textile...
e
e
Levasil® 200S/30: "cationic silica sol" = alumina-coated silica NPs
e
e
OH
Modification of the NPs in the aqueous sol :
0        Sl° )
e (
OPA
0=P
Í/OH
/
DEPA
o
0=P
OH
X)H
OPA ; hydrophobic R group DEPA ; hydrophilic R group
Tuning interactions between nanoparticles in aqueous solutions
iC
o.
lisímu ;i»Ih G(f t*s HoniDtUf
Grafting oxide NPs in aqueous colloidal solutions
		50-i
1 OH J 1		
f /		40-
j 1	>	
	E	
^ j	—	30-
r o		
> j	c	
UM OH	a> o	20-
	Q. «J	
OPA DEPA	d) N	10-
Zeta potential
Rapp (DLS)
o
0,0
OPA
Grafting density / P nm
0,3 P/nm2
0,5 P/nm2
3,2 P/nm2
Grafting density / P nm
• OPA, DEPA: slight decrease of ZP
• OPA: aggregation increases with grafting density hydrophobic interactions
iC
o;
Oxide nanoparticles: cheap, "green" syntheses in aqueous media,
sols stabilized by electrostatic repulsion
Inks, paints, nanocomposites: need for organosoluble nanoparticles
Langmuir 2015, 31, 10966-10974
iC
o;
Phase transfer of Ti02 particles
Parameters influencing the transfer
f   rf   rt      f     t    ^ ^
^ o*  0& oN% $r 3
0     0.8    1.7 2.4 PA concentration (mmol/g)
1     5 23 Sol concentration (wt%)
Alkylphosphonic acids with chain > 5 Carbons ca 4-5 P/nm2
Works even for high sol concentration
Langmuir 2015, 31, 10966-10974
r
Transfer of aggregated nanoparticles
Variation of NP dispersion
pH variation
salt addition
600 -
400 I
CO
Q
200
pH 2
pH 4
pH 5
600 -
400
P
200
0 4 5 6
NaCl content (wt%) 44
Transfer of aggregated nanoparticles
r
Variation of NP dispersion
pH variation
salt addition
R(DLS) organic phase R(DLS) aq
600 -
400
CO
p
200 1
0
pH 2
pH 4
pH 5
-1-1-1-1—i-1-1-1-1-1-1-1-1-1-1-1-1-1-1—
600
400 V
CO
P
200 V
0
R(DLS) organic phase
R(DLS) aq
0
NaCl content (wt%)
6
44
Transfer of aggregated nanoparticles
Deaggregation during phase transfer / surface modification
R(DLS) organic phase R(DLS) aq
600 -
400
CO
P
200 -
0
pH 2
pH 4
pH 5
-1-1-1-1—I-1-1-1-1-1-1-1-1-1-1-1-1-1-1—
600
400 -
CO
P
200 -
0
R(DLS) organic phase
R(DLS) aq
0
NaCl content (wt%)
6
44
iCGS
Interlayer grafting
collaboration Y. Sugahara, Waseda, Tokyo
HLaNb207.xH20 : ion-exchangeable layered perovskite
AAAA
♦♦♦♦
n-propanol ->
(10 mass% water)
D-decanol
(1 mass% water)
organophosphonic acid
->
2-butanone
(1 mass% water)
XRD
0       5       10      15 20 Number of carbon atoms in alkylchain
Chem. Mater. 2009, 21 4155
■CG!
collaboration Y. Sugahara Tokyo
K4Nb6017-3H20 : two distinct interlayers, selective intercalation
V * * * *s
Hexaniobate layer
NMe2(C18H37)2CI ->
Intercalation
X
/ / / /
it tit
O^^OH OH y
6 0  0   0 0
0 0 0 0
Grafting
N(C12H25)H3CI
\,,,
AAA
/ / / / / / / / / /
OH
OH
bo o""g"b
XRD: selective grafting
Langmuir 2014, 30, 1169
iCGM Selective interlayer grafting
Exfoliation in CH3CN: leads selectively to hydrophobic mono- and bilayers
AFM
ö c
ö ö 0 0
sonication
CH,CN
Exfoliation
2.9 nm
ÓOOOŮ
sonicaticTi
O
>0
CH3CN
2.1 nm
Janus monolayers?
Langmuir 2014, 30, 1169
Conclusions
Phosphonate coupling molecules
• complementary of silanes and thiols
• anchoring to the surface by M-O-P bonds only
• wide range of inorganic substrates and terminal groups
Powerful tool for the control of surface and interface properties
Acknowledgments
A. Vioux, G. Guerrero, J. Alauzun
PhDs / Post-docs
Vincent Lafond Florence Brodard Stephanie Lassiaz Jeremie Soullier Julien Amalric Charlene Presti Celine Schmitt
Collaborations
C. Gervais, F. Babonneau (UPMC) J.-Ph. Lavigne, D. Noel (INSERM) J. Oberdisse, C. Genix (L2C) G. Ramanath (RPI) Y. Sugahara (Tokyo)
Funding
CNRS, MENRT
Labex Chemisyst
Institut Frangais du Petrole
Arc International
Rhodia