Dendritic and Core–Shell–Corona Mesoporous Sister Nanospheres from Polymer–Surfactant–Silica Self-Entanglement

Article abstract of DOI:10.1002/chem.201704714

Mesoporous nanospheres are highly regarded for their applications in nanomedicine, optical devices, batteries, nanofiltration, and heterogeneous catalysis. In the last field, the dendritic morphology, which favors molecular diffusion, is a very important morphology known for silica, but not yet for carbon. A one-pot, easy, and scalable co-sol–gel route by using the triphasic resol–surfactant–silica system is shown to yield the topologies of dendritic and core–shell–corona mesoporous sister nanospheres by inner radial phase speciation control on a mass-transfer-limited process, depending on the relative polycondensation rates of the resol polymer and silica phases. The trick was the use of polyolamines with different catalytic activities on each hard phase polycondensation. The self-entanglement of phases is produced at the {O^?, S⁺, I^?} organic–surfactant–inorganic interface. Mono- and biphasic mesoporous sister nanospheres of carbon and/or silica are derivatized from each mother nanospheres and called “syntaxic” because of similar sizes and mirrored morphologies. Comparing these “false twins”, or yin and yang mesoporous nanospheres, functionalized by sulfonic groups provides evidence of the superiority of the dendritic topologies and the absence of a shell on the diffusion-controlled catalytic alkylation of m-cresol.

Full text of DOI:10.1002/chem.201704714

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Title: Dendritic and Core-Shell-Corona Mesoporous Sister
Nanospheres from Polymer-Surfactant-Silica Self-Entanglement
Authors: Kun Zhang
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DOI: 10.1002/ ((please add manuscript number))
Article type: Full Paper
Dendritic and Core-Shell-Corona Mesoporous Sister Nanospheres from Polymer-
Surfactant-Silica Self-Entanglement
Kun Zhang,* Tai-Qun Yang, Bing-Qian Shan, Peng-Cheng Liu, Bo Peng, Qing-Song Xue, En-
Hui Yuan, Peng Wu,* elén Albela, Laurent Bonneviot*
Prof. Kun Zhang, Tai-Qun Yang, Bing-Qian Shan, Peng-Cheng Liu, Bo Peng, Dr. Qing-
Song Xue, En-Hui Yuan, Prof. Peng Wu
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry
and Molecular Engineering
East China Normal University
Shanghai, 200062, China
E-mail: kzhang@chem.ecnu.edu.cn, pwu@chem.ecnu.edu.cn
Dr. Bélen Albela, Laurent Bonneviot
Laboratoire de chimie, Ecole Normale Supérieure de Lyon, Institut de Chimie de Lyon
Université de Lyon
46 Allée d’italie, 69364 Lyon cedex 07, France
E-mail: laurent.bonneviot@ens-lyon.fr
KEYWORDS: self-assembly, hybrid materials, nanoparticles, porosity, Solid acid catalysis.
ABSTRACT: Mesoporous nanospheres are highly regarded for their applications in
nanomedicine, optical devices, batteries, nanofiltration and heterogeneous catalysis. In the
latter field, the dendritic morphology favoring molecular diffusion is a very important
morphology known for silica but not yet for carbon. A one-pot, easy and scalable co-sol-gel
route using the triphasic resol-surfactant-silica system is shown to yield the topologies of the
title by inner radial phase speciation control on a mass-transfer limited process depending on
the relative polycondensation rates of the resol polymer and silica phases. The trick was the
use of polyolamines having different catalytic activities on each hard phase polycondensation.
The self-entanglement of phases is produced at the {O-, S+, I-} organic-surfactant-inorganic
interface. Mono- and biphasic mesoporous sister nanopheres of carbon and/or silica are
derivatized from each mother nanospheres and called "syntactic" as having similar size and
mirrored morphologies. Comparing these "false twins" or yin and yang mesoporous
1
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nanospheres functionalized by sulfonoyl groups evidences the superiority of the dendritic
topologies and the absence of a shell on the diffusion-controlled catalytic alkylation of m-
cresol.
1. Introduction
A plethora of living systems such as bones, teeth and shells of various compositions
inspire chemists to develop entangled inorganic-organic phases.[1] In diatoms, highly pure
biosilica is produced selectively by specific enzymes activating the Si-OH polycondensation.[2]
These catalytic sites mimicked here by polyolamines (POA) allow fast condensation even
around pH neutrality.[3] The molding amphiphilic phospholipids of membranes are replaced
by single long chain alkyltrimethylammoniums, as in the syntheses of the emblematic
mesostructured porous silicas MCM-41 and MCM-48.[4] The structural control is obtained on
both array and size of pores, combining hard and soft matter like in the biogenic materials.[1a,
1j, 3-5] Spontaneous soft-soft and hard-hard entanglements of matter reported in tubular vesicles,
in de-mixing microphases and in ceramics remain rare.[6] Not yet understood nor described in
Mother Nature, spontaneous assembly of three phases is even more challenging and scarce.[7]
The easy-to-perform synthesis proposed here concerns the class I type of structural
nanohybrids adopting a variety of inner topologies and pore arrays. It proceeds from the
spontaneous entangled growth of two hard phases – resol and silica – mediated by soft matter
– a water-surfactant phase.
The impressive progress in sol-gel chemistry of silica on the design of porous
nanoparticles in the last 20 years was mirrored by that of porous carbon nanoparticles with
increasing control on shape, topology, size and pore structure.[8] Very open stellar porosity in
silica nanoparticles are obtained introducing specific catalytic additives or playing with
9]
interfacial growth control.[3,
Resorcinol- or phenol-formaldehyde condensation self-
assembled with a neutral surfactant yields also monodisperse nanospheres using high
2
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dilutions.[10] Surprisingly, the addition of silica precursors to styrene or to resol and phenol-
formaldehyde polymer precursors leads to new morphologies with a loss on the control of the
10h, 10n]
size.[7,
Monodispersed hollow carbon-silica porous nanospheres were recently
produced by one-pot synthesis by the group of Cao et al. using either classic thermal
activation or microwave assisted.[11] Concomitant control on morphology, size and porosity on
polymer-silica nanohybrids can also be obtained by co-assembly of preformed resol and silica
nanophases inside films formed by the evaporation induced self-assembly process (EISA).[7b]
Hard templating, high dilution, water oil emulsion or any sequential routes are discarded in
the present work to keep the focus on easy up scaling. We propose instead to grow together
polymeric and siliceous hard nanophases with positively-charged micelles in conditions
adapted from those of the group of Cao with in addition the use different specific catalytic
amines for the control on the relative rate of silica and resol condensations. [11]
We will discover from transmission electron microscopy (TEM) that their inner structure
is fingerprinting a mutual though asymmetrical action of one phase on the other: the nascent
silica phase scaffolding the growth of the resol phase. The former considered as yang and the
latter as yin emphasizes that they are not really twin phases as we shall see. The word
“syntaxy” is meant to designate any mechanism by which two solid phases are grown by self-
assembly from their molecular precursor leading therefore to “syntaxic” nanophases. It is built
from two ancient Greek words sun for syn- meaning “together” and tikto for -taxy or -taxic
meaning “to give birth and/or to grow” (SI). Among three topologies cited in the abstract, two
are new and all are thoroughly investigated not only entangled but also separated. The word
topology is related here to any specific speciation of composition or density pattern, while
pore array is related to the pore shape and distribution, as we shall observe from energy
dispersive X-ray (EDX) analysis mapping and TEM images (SI). The void between the yin
and the yang solid phases will be characterized using N2 physisorption. The effect of the
microporous silica shells on molecular diffusion-limitation will be evidenced comparing
3
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nanospheres of various topologies as supports for the acid catalyzed tert-butyl alkylation of
m-cresol.
2. Results and Discussion
2.1. A scalable synthesis of hybrids materials and their derivatized biphasic and
monophasic porous sister phases.
The polymer-surfactant-silica – PSS – mesoporous nanospheres – MNS – were obtained
by hydrothermal treatment at 80°C of slightly basic solutions prepared at room temperature
from ethanol and water as co-solvents, cetyltrimethyl ammonium bromide – CTAB – as
surfactant, tetraethylorthosilicate – TEOS – as silica precursor, a resorcinol-formaldehyde
mixture – RF – as resol precursor and a catalytic amine x (= 1-3); 1 = TEAH3
(triethanolamine), 2 = AHMPD (2-amino-2-(hydroxymethyl)-propane-1,3-diol) and 3 for
ammonia (Fig. 1). After filtration and drying for 24 h at 80°C , ethanol free polymer/water-
surfactant/silica triphasic nanospheres denoted as PSS-MNS-x were recovered and freed from
the surfactant by extraction yielded then biphasic polymer–silica hybrids – PS – noted PS-
MNS-x. Carbonization of PSS or PS hybrids respectively, yielding the carbon-silica hybrids
*CS-MNS-x and CS-MNS-x (derivatization sequence and sample the nomenclature in Fig. 1).
Etching the silica nanophase yielded the corresponding polymer or carbon yin nanosphases P-
MNS-x, *C-MNS-x and C-MNS-x, while their yang silica counterpart S-MNS-x were
obtained after calcination in air. Note that the composition of the mother liquor was very close
to that of regular MCM-41 synthesis used previously to investigate the surfactant-silica
system.[3] It differs mainly from a higher dilution (3.5 times), the addition of ethanol and a
surfactant/silica ratio twice higher to reach the conditions for the targeted dendritic topology.
Adding resorcinol and aldehyde resulted to a mother liquor of similar composition than that
used to produce hollow spheres by the group of Cao.[7a] The main difference was the nature of
the amine while the concentration of resorcinol was three times increased to finally obtain the
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dendritic morphology. The polymer and silica yields for the synthesis of PSS-MNS-1 were 55
and 43%, respectively and 44 and 63% for the other two amines (x = 2 and 3). These
syntheses are very robust and can be scaled up to the kilogramme scale (see experimental
part).
2.2. Electron microscopy investigation: an amine dependent topology.
The size and shape of the hybrid systems were investigated using scanning electron
microscopy (SEM) while monophasic systems revealed a better inner contrast of their
topology and pore array using TEM (Figure 1). According to SEM images, amine 1 favored a
narrow distribution of sizes, with nanospheres comprised between 100 and 150 nm (Figure
1a). With amine 1, the silica nanospheres possessed a uniform (U) dendritic (De) topology,
with pores having a thin finger-like wall (dendrite) and external apertures ranging from 9 to
17 nm (nomenclature in SI, Figure 1d, 2a, and Table 1). This so-called U-De silica
morphology had in common with its carbon counterpart the size and the uniform topology.
However, the latter exhibited rather flat walls with voids that can be view as a perforated-veil
denoted U-Pv (Figure 1g, 2d). Grown in very similar conditions without resol precursors,
silica adopted a raspberry type of pore array, U-Rb (Figure 5Sb). Nonetheless, the actual U-
De topology is more alike the stellar morphology (St) obtained also without resol precursor
while using tosylate as counter-ions instead of bromide.[3] The main difference consists to
thicker wall at the center than at the periphery leading to a slightly denser core and a wide
open outer part in contrast with U-De (Figure 2g).[3]
In comparison, amines 2 and 3 yielded larger nanospheres of ca. 400 nm and ca. 600 nm,
respectively (Figure 1b, 1c and Figure S1B). The nanospheres of S-MNS-2 exhibited a core-
shell-corona (CSC) topology with a dense shell, 50-70 nm thick, unexpectedly located inside
of the nanosphere with low density cores and coronas (Figure 1e, 2b). The S-MNS-3
exhibited a typical core-shell (CS) topology (Figure (1f, 2c). In SMNS-2 and -3, the shells
presented center-radial micropores with diameters smaller than 2 nm while the cores were
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much less structured, particularly in S-MNS-2 (Figure 2b and 2c). In comparison to the yang
S-MNS-x nanophases, the yin carbon counterpart, C-MNS-x, exhibited similar inner
topologies with an inverted contrast and, definitively, a less defined pore structure (Figure 1g,
h and i). These observations are consistent with the yin being entangled together with the yang
nanophase, each adopting complementary inner structures, called syntaxic.
2.3. Elemental mapping EDX analysis: growth with competitive mass transfer between
precursors.
Mapping the composition using energy dispersive X-ray (EDX) analysis indeed
confirmed that both C and Si atoms were present in each hybrid nanoparticle whatever the
base at play (Figure 3). The map of Si atoms matching well that of O atoms traced the SiO2
nanophase while that of C atoms traced the resol nanophase (Figure 3, row 5). No phase
segregation between particles could be detected by EDX in CS-MNS-1. Nonetheless, a close
look at the periphery where silica dendrites showed more clearly that the position of the
carbon phase did not fully coincide with the position of the SiO2 phase suggesting that one
phase was wrapping up the other (Figure 3, column 1). Conversely, the elemental mapping of
CS-MNS-2 and -3 confirmed some phase speciation, indeed, the dense shells observed on the
TEM images were silica-rich zones. This is in striking contrast with the EDX fingerprint of
hollow spheres where both phases are equally present in the shell while the core appears
empty.[11a] This is consistent with a faster development of the resol network than in C-MNS-1,
which was favored over that of silica at the early stage of the synthesis. The presence of a
dense shell inside the nanosphere in CS-MNS-2 evidenced two inversions of the tendency.
The first one took place at an intermediate stage of the synthesis while the second at the last
step of the growth, producing a less dense corona. Using ammonia instead produced this
inversion only at the very end of the synthesis, generating a silica dense outer shell and,
therefore, no corona (CS-MNS-3, Figure 3, column 3). The phase speciation in the core can
be assigned to a temporary faster condensation rate of the polymer phase, producing a
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concentration gradient of its precursors around the nucleus. With time, the increasing gradient
becomes enough disfavoring for the polycondensation rate of the silica takes over that of the
resol. In turn, during the formation of the silica-rich shell, this was now the built up of the
concentration gradient in silica precursors that brought the possibility to reach a second
breaking point before the end of the synthesis. This occurs in S-MNS-2 where a carbon-rich
corona can be formed before the end of the synthesis. In other words, a mass transfer
limitation takes place as the molecular precursors have to diffuse among micelles that, in turn
progressively stick one with another during the growth. Then, one understands why the
relative rate of polycondensation of each phase is a crucial parameter to reach the composition
homogeneity. In fact, polyolamine 2 has a lesser catalytic effect than polyolamine 1 and
generates also a higher pH, both criteria are favoring of the resol condensation. This slower
silica polydensation results to a decrease of its concentration in the core. Ammonia is even a
worse catalyst than 2 for silica condensation generating also higher pH and pushed the trend
further explaining the silica-rich outer shell (pH and pKA in Table S1). As the pH itself
decreases gradually down to a final value of 8.1 tuning both phase concentrations all along the
synthesis is a very subtle game (~ 1.2 % residual deprotonation of resorcinol, Table S1).[1j, 12]
The mass balance in the triphasic nanospheres is also consistent with this point of view as the
presence of a silica-rich shell is marked by a higher proportion of this phase in the
composition (resol/surfactant/silica mass ratio of 18/57/23 in PSS-MNS-1 and 15/49/36 in
PSS-MNS-2 and -3, measured from TGA, Figure S2). The formation of the CSC topology
was a lucky gift as it brought us a lot of insights on the mechanism. The subtle competitive
mass transfer between both hard phases precursors during the growth process precludes any
precise prediction on the radial composition and fully justifies a trial and error approach,
guided by the effect of the parameters described here (Fig. S4).
2.4. The leading drive of the silica nanophase scaffolding the resol nanophase.
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Changing the amine concentration or the solid phase precursor concentration indeed
affected both topology and pore array (Fig. S3-S5). The uniform topology of PSS-MNS-1
nanospheres was lost at low TEAH3 concentration, leading an inverse core-shell speciation of
composition in comparison to PSS-MNS-3 (Fig. S3 and S4). The rational explanation is found
in the decrease of pH disfavoring further the polycondensation of the resol phase over that of
the silica phase, the latter still taking advantage on the few of catalytic amines 1 still present.
Conversely, too high TEAH3 concentrations generating too high pH favored the nucleation of
each phase independently forming nuclei with heterogeneous composition. In the present
condition of concentration and pH that differ slightly from our previous investigation, we
verified that this is effectively the U-Rb topology that is produced (Fig. S5b).[3] Conversely, in
the absence of silica, the resol polymer is known to form large and non-porous spheres of ca.
1.0 μm, which we also confirmed in our particular conditions (Fig. S5d).[10d] Consistently,
carbon-rich areas in CS and CSC topologies developed less defined porosity than silica-rich
areas. The structural synergy observed between the entangled phases is additional fingerprint
of the syntaxy principle while the strong topology dependence on precursor concentration
further support the hypothesis of diffusion controlled nucleation process starting from very
small clusters of micelles-precursor composites.
2.5. A class I nanohybrid: two hard nanophases sandwitching a soft hard phase of few
nm thick.
The porosity of the surfactant-free hybrid nanospheres was confirmed by N2 sorption
isotherms (Fig. S6 and S7, and Table 2). The presence of the shells was the cause of the
porosity loss in PSS-MNS-x (x = 2 or 3), which was assigned to pore plugging by the weakly
13
reticulated resol phase (see FT-IR and C NMR, Fig. S8 and S9). The carbonization solved
this problem revealing large surface areas (300-800 m2g-1) and large pore volumes (1 to 1.7
ml/g) (Table 2), consistent with the different topologies (Fig. 2).
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The volumetric surface areas (surface developed per unit of volume) that better describe
the spatial occupancy are indeed rather close, supporting the idea that both entangled
nanophases are facing one to the other through a common interface (Fig. 4A and Table 2).
Strikingly, the well-defined pores of 5 nm in PS-MNS-1 evidenced that both yin and yang
nanophases were split apart by a distance that shrank by ca. 20% after carbonization (Fig. 4).
In addition, the absence of any signal at 64 ppm after mild carbonization at 350°C excluded
the formation of covalent Si-O-C bridges between both hard nanophases, advocating for the
formation of a class I type of nano-hybrids (Figure S9).[7b]
2.6. Topology dependence on a diffusion-controlled catalytic reaction.
Applying these nanospheres as support for a reaction of industrial importance was
appealing particularly to test whether dendritic morphologies were advantageous. We chose
the catalytic tert-butyl alkylation of m-cresol that run in liquid media where molecular
diffusion-limitation is crucial. Then, the monophasic X-MNS-x nanospheres (X = C or S)
were compared to benchmark heterogeneous catalysts for this reaction (Fig. 4B). Their
surfaces were functionalized with acidic sulfonate groups, leading to S-MNS-x-SO3H and C-
MNS-x-SO3H nanospheres (level of sulfonation available in SI).[10r, 13] The references were
the emblematic acid heterogeneous catalysts ZSM-5 (Si/Al = 50) and USY-1, 2 and 3 (Si/Al =
5.2, 12 and 36.9, respectively) (Table S2). The highest conversion, ~ 60 and 66%, using S-
MNS-1-SO3H and C-MNS-1-SO3H, respectively was attributed to their highly open porosity,
being even better than USY-2 and 3, presenting themselves large voids created during the
dealumination treatment (Table S2 and Fig. S10). By contrast, S-MNS-2-SO3H and,
particularly S-MNS-3-SO3H, were much less active and compared better with the
microporous ZMS-5 and USY-1 presenting mainly micropores and the largest diffusion
limitation. The carbon yin nanospheres C-MNS-x-SO3H possessing no dense shells exhibited
intermediary conversions scaling better with their exposed surface area (Table S2, Fig. 5).
The more advantageous selectivity/conversion ratio obtained with the silica support is
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probably due to its larger organic coverage and its higher hydrophobic surface than that of the
sulfonated carbon nanospheres. This clearly shows that shell-free and wide-open pore
topologies are highly favorable for heterogeneous catalysis, as they minimize molecular
diffusion-limitation. After four cycles of use of C-MNS-1-SO3H, the catalyst still maintains a
high activity and selectivity (Fig. S11), and the SEM observations show that their morphology
and structure are maintained after long-term use (Fig. S12). Conversely, the presence of the
silica shell is certainly more favorable for other applications like electrical storage or drug
delivery, though biocompatibility remains to investigate.[1i, 8b, 14]
2.7. Syntaxic entanglement at the {O-, S+, I-} interface.
The well-known biphasic silica-surfactant self- assembly mechanism is likely to be
extrapolated to the present three-body mechanism.[6a] In the former, the silicate oligomers
condense into nanoflakes.[3] These flakes merge together crosslinking the micelles one with
the other. Different morphologies of silica nanospheres cited above are then produced,
depending on the micelle coverage (Fig. 1g-i). In In the three-body mechanism, the
resorcinolate anions (pHi ~ 10.4, Table S2) are likely adsorbed on the micelles together with
the silica precursors.[11a] The latter first form silica-nanoflakes, catalyzed by the amine 1 (step
I of the synthesis, Fig. 5). These flakes facilitate the micelle merging and also increase the
local concentration in resol precursors, favoring the initiation of the resol polycondensation
(step II, Fig. 5). The growing silica-network is progressively mirrored by the resol-network,
with a water-surfactant layer in between (step III, Fig. 5). Note that a lower coverage by
silica-flakes is expected to generate lower density of hard matter, i. e., larger pores. This is
effectively observed here changing polyolamine 2 for polyamine 1 leading to larger pores of 9
nm in PS-MNS-2 (Fig. 4A). This mechanism explains how the yang silica nanophase triggers
the nucleation and scaffolds the shape of the yin resol nanophase, both adopting syntaxic
forms, as a hand fits a glove (Fig. 5). It explains also why the solid phases grow separately,
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split by a distance defined by the water-surfactant layer. This characteristic distance of 5 nm
in the as-made material matches well with the 14 nm of the single nanophases assuming that
the pore wall thickness of the eliminated phase was approximately 4 nm (Fig. 4C). Note that
the same pore wall thickness in PS-MNS-2 explains also the shift of pore size from 8-9 nm to
20-22 nm in the single phases, P- or C-MNS-2 and S-MNS-2. In the as made PSS-MNS-x
materials, this interface is denoted as {O-, S+, I-} according to the notation for the surfactant-
inorganic association of matter O- designating the organic phase.[15]
2.8. Co-assembly and syntaxy, two different strategies of synthesis.
Synthesizing triconstituent nanospheres by co-assembly is a multi-pot approach where
both hard phases are pre-condensed at different pH’s. The organic and inorganic phases are
then mixed together before introducing the neutral surfactant, S0.[7b] The templated self-
assembly takes place at this last step at, what we propose to call, a {S0, (O-I)0} interface. Both
organic and inorganic phases sharing covalent C-O-Si bridges led to a class II type of hybrid.
As a consequence, eliminating one of the nanophases generates pores inside the walls of the
remaining phase that are smaller than those templated by the surfactant, in sharp contrast with
the present case. Though co-assembly and syntaxy are both belonging to the family of
templated self-assembly processes, the former operates on preexisting hard nanophase(s)
while the latter takes place with molecular precursor(s). Syntaxy belongs to the templated
molecular self-assembly in the classification of Whitesides.[16]
2.9. Comparison with other one-pot polymer-surfactant silica systems.
In different conditions set for one pot synthesis than the co-assembly route, Zhang et al.
discovered that adding silica to the resorcinol-CTAB system lead to unprecedented variety of
shapes and topologies – tubular to spherical – and inner topologies – hollow and yolk-shell.[7a,
11] Applying solvent adjustment to the one-pot approach led also Hou et al. to control the size
of hollow nanospheres while Zhou et al. shortened the ageing time to 1 hour using the
[11]
assistance of a microwave irradiation.
To target the U-De topology, the resorcinol was
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three times more concentrated and the ammonia was replaced by a polyolamine. Surprizingly,
coming back to ammonia (amine 3) with this high resorcinol concentration led us to the CS
polymer-rich core morphology instead of hollow polymer-silica nanohybrids.[11a] This
indicates that increasing three times the concentration of resorcinol completely change the
kinetics and the topology. This shows how much these syntheses are sensitive.
The synthesis interface proposed here is certainly the same in the hybrid nanospheres in
both cases. In neither absence of specific information on the type of nanohybrid (I or II) nor
any comparison between the porosity of the monophasic and the biphasic systems preclude
any further comparison. The difference is the mechanism. We advocate for a nucleation
growth starting from individual micelles decorated by the both solid phase precursors. It
explains the evenly distributed phases in the U-De topology and the radial speciation from the
center of the nanosphere for CSC and CS morphologies. Conversely, the size, the shapes and
the hollow core are preferentially described by precursors diffusing from the outside to the
inside of already formed large aggregates of micelles (emulsion seen few minutes after
formaldehyde addition, before the introduction of TEOS). As this mechanism is not
compatible with our observations, the higher concentration of resorcinol may disfavor their
mechanism by triggering ours. More investigations are still needed to clarify the situation.
2.10. Syntaxy among the other strategies of templated synthesis.
The mechanism of formation of the present yin-yang entangled pairs of nanophases is
obviously related to the nano objects of different shapes produced by the group of Cao. 19, 46-47
To clarify the situation with the solid phases obtained by the co-assembly route proposed by
the group of Zhao, [7b] the molecularly self-assembled material needed a specific qualification
that we call syntaxic. Semantically, this principle includes biphasic soft-hard systems and
therefore the synthesis of the emblematic MCM-41 and SBA-n.[3-6, 8f, 15] Practically, one may
exclude the biphasic systems that leave behind only one solid phase and no syntaxic sister
phases as a complementary signature of the mechanism. In contrast, a triphasic hard-soft-hard
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system produces for a single morphology at least 3 syntaxic solid phases (here up to 7 from
the derivatization scheme of fig. 1). This is the analysis of the set of syntaxic solid phases
makes the difference with the co-assembly route, which de facto is not syntaxic (see above).
Hard templating is another pathway that is also non-syntaxic like the liquid crystal templating
route assuming a liquid preorganization of the template.[17] Interestingly, the folded sheet
material (FSM) resembling to MCM-41 is derivatized from a lamellar kanemite swelled by
cationic surfactant. [17b] It is therefore also non-syntaxic and could be classified as a templated
phase transition (TEPT) route. Our classification based on mechanistic specificity complete
the strategic map proposed lately by Liu et al..[10r]
3. Conclusions
It has been shown that the catalytic control on the relative rate of polycendensation of the
two hard phases in the co-sol-gel synthesis of the resol-CTAB-silica system lead to new
morphologies. Using amine catalyzing specifically the silica condensation at the expense of
the resol polycondensation allowed us to move from the uniform dendritic, to phase
partitioned core-shell-corona and core-shell topologies. This radial speciation is typical of a
mass transfer limitation of the solid precursor during the growing process explaining why a
variety of topologies can be observed. To our knowledge, the derivatization of the dendritic
hybrid into the carbon sister nanosphere is up to now the sole route available to generate
monodisperse dendritic carbon nanospheres. The core-shell-corona is also a novel topology
not only for carbon but also for silica. The proposed mechanism is comparable to that of the
biphasic surfactant-silica system where silica drives the porosity of the polymer phase, acting
as a co-template together with the surfactant. This asymmetry led to “false twin” yin and yang
pair of phases. This actual three-body system takes place at an organic-surfactant-inorganic
{O-, S+, I-} interface and led us to define a new principle called syntaxy. The variety of
topologies obtained for two hard phases at a time each of the derivatized in several mono or
biphasic sister phases is particularly attractive for comparative investigations at the nanoscale.
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It is exemplified here in the diffusion controlled catalytic alkylation of m-cresol where the
shell free phases are the most active and selective. The present mechanism likely amenable to
other systems paves the way for the syntheses of novel multiphasic nanohybrids, and novel
applications in chemistry, material sciences, and nanomedicine.
4. Experimental Section
Syntheses of entangled resol-CTA-silica triphasic nanospheres from polyolamine 1: The
dendritic mesoporous resol-CTA-silica nanospheres (PSS-MNS-1) were synthesized using a
one-pot soft-templating method (Fig. 1). A typical synthesis of dendritic PSS-MNS-1 was
performed as follows: triethanolamine (TEAH3) aqueous solution (10.6 g; pKa = 7.8) was
mixed with a solution containing resorcinol (5.0 g), CTAB (5.0 g), absolute ethanol (EtOH,
200 mL), and deionized water (500 mL), then stirred for 0.5 h. Subsequently, formaldehyde
solution (5.0 mL, 37 ~ 40 wt%) was added and continuously stirred for 2 - 5 min. Then TEOS
(25 mL) were added to the reaction solution and stirred for 24 h at room temperature. The
final molar composition of the sol-gel mixture is 1.0 SiO2 : 0.40 Resorcinol : 0.75 HCHO :
0.12 CTABr : 0.66 TEAH3 : 30 C2H5OH : 248 H2O. The reaction mixture was further heated
°
for 24 h at 80 C under a static condition in a Teflon-lined autoclave. The obtained dendritic
mesoporous resin-silica composite nanospheres were recovered by filtration and air-dried at
o
80 C overnight yield 16 g and were denoted as for with 1 standing for the use of TEAH3 as
alkali source (see below for the other bases). The resol/silica/surfactant/water mass ratio was
ca. 18/59/23, according to TGA see Fig. S2. The yields in resol and in silica were 55 and 43%,
respectively. A successful up scaling using a 20L vessel demonstrated that a 60 L vessel filled
at 75% (45 L) is need for 1 Kg of PSS-MNS-1(i.e. 410 g of dry PS-MNS-1).
Syntheses of MNS using either amine 2 or 3: Core-shell-corona (CSC) or core-shell (CS)
mesoporous hybrid nanospheres were formed and designated PSS-MNS-2 (or -3) when
14
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aqueous 2-amino-2-(hydroxymethyl)-propane-1,3-diol (2 for AHMPD, pKa = 8.1) and
ammonia (3 = NH3∙H2O, pKa = 9.2) were used instead of TEAH3 for the same solution
composition. The yield in air-dried as-made hybrid nanosphere was 14.9 and 15.1 g for amine
2 and 3, respectively. The resol/silica/surfactant/water mass ratio was ca. 15/49/36, according
to TGA see Fig. S3. The yield was respectively 44 and 63% in resol and in silica producing ca.
940 g of PSS-MNS and 550 g of dry PS-MNS in the same up scaling conditions given for
1Kg of PSS-MNS-1.
Syntheses of C-MNS-x and S-MNS-x carbon or silica single-phase nanospheres: The triphasic
nanospheres PSS-MNS-x (x = 1, 2, 3) were carbonized in inert atmosphere using a tubular
furnace, raising the temperature (3°C/min) up to 900 °C and maintaining this temperature for 3
h under a N2 gas flow. After cooling, the silica was removed by immersing the obtained
carbon-silica composites in 10 wt% HF aqueous solution at room temperature for 24 h,
followed by washing with water. The mesoporous carbon nanospheres were dried overnight.
When the surfactant was chemically removed before carbonization, the solid was denoted C-
MNS-x while direct carbonization of the as-made nanosphere led to the material denoted as
*C-MNS-x. The dendritic mesoporous silica nanospheres S-MNS-x were obtained by direct
calcination of PSS-MNS-x at 550 °C for 6 h in air.
Material characterizations: The X-ray diffraction (XRD) patterns were collected on a Rigaku
Ultima IV X-ray diffractometer with Cu Kα radiation (λ = 1.5405 Å) at 40 kV and 40 mA.
Nitrogen adsorption-desorption isotherms were recorded at 77 K on a Quantachrome (O2108-
KR-1) after activating the sample under vacuum at 473 K for at least 10 h. The SEM images
were captured using a Hitachi S-4800 microscope. TEM analyses were performed using a
JEOL 2010F microscope equipped with a field emission gun and operating at 200 kV. Point
by point Energy dispersive X-ray spectroscopy (EDS) providing the concentration profiles of
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oxygen, silicon and carbon atoms through the nanospheres were measured using the
transmission electron microscope in scanning mode. FT-IR spectra were recorded on a
Nicolet Fourier transform infrared spectrometer (NEXUS 670) diluting the sample in a fine
KBr powder that was pressed into pellet. Solid 13C CP MAS NMR measurements were
collected using a VARIAN VNMRS-400WB spectrometer. For 13C (100.6 MHz), a 6 μs (θ =
π/2) pulse was used with a repetition time of 3 s.
Preparation of C-MNS-x-SO3H and S-MNS-x-SO3H catalysts: The preparation of X-MNS-x-
SO3H catalysts (X = S for silica or C for carbon, x = 2 or 3) followed a recipe described in ref.
42. The sulfonation of the 0.3 g mesoporous carbon nanospheres (C-MNS-x) were carried out
in a Teflon container set in a Teflon-lined autoclave where the powders were contacted with
the vapor from 5 mL 50% SO3/H2SO4 at 383 K for 24 h. The sulfonated samples, X-MNS-x-
SO3H, were washed with hot distilled water (> 353 K) and filtrated until no sulfate ions were
no longer detected in the filtration water, and dried at 373 K overnight in air. Sulfonic acid
functionalized mesoporous silica nanospheres S-MNS-x-SO3H were prepared as follows: the
o
S-MNS-x sample (1 g) was dried at 120 C, and then 3-mercapto-propyltriethoxy-silane (2
mmol) in dry toluene (40 mL) was introduced. The mixture was refluxed for 6 h, and the solid
was filtered off, washed with toluene and acetone, and air-dried. The -SH groups were
converted into -SO3H groups by oxidation using a mixture of aqueous H2O2 (30%, 10 mL)
and CH3OH (30 mL) for 6 h at a reflux temperature. After filtration and washing with water
and ethanol, the sample was then acidified in 2.0 M HCl solution for 1 h, followed by washing
o
with water until neutral pH and drying at 100 C for 6 h. The number of acid sites were
measured from NH3 TPD desorption (Table S2). For control experiments, zeolite catalysts of
ZSM-5 (Si/Al = 50), and USY-1, 2 and 3 with varied Si/Al molar ratios (Si/Al = 5.2, 12 and
36.9) and tunable hierarchical porosity were obtained commercially. All the zeolites were
16
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10.1002/chem.201704714
Chemistry - A European Journal
converted into proton type by ion-exchanged with NH4NO3 solution followed by calcination
at 773 K for 6 h.
Catalytic test: The alkylation reaction of m-cresol and tert-butyl alcohol was performed by
stirring the mixture of 0.1 g catalyst, 4.0 g m-cresol and 3.4 g tert-butyl alcohol at 403 K for 2
h. The product identification was obtained from gas chromatograph-mass spectrometer
(Agilent HP6890/5973N) calibrated with pure molecules, that are all commercially available.
Precise quantification was obtained from a Shimadzu 14B gas chromatograph equipped with
an OV-1 capillary column.
Supporting Information
Supporting Information is available from the Wiley Online Library or from the author.
Acknowledgements
The research was conceived and designed by ZK and WP with the follow up of LB. The latter
proposed also the mechanism and the nomenclature, designed the figures and wrote the article
with the assistance of ZK and BA. LB dedicates this paper to his inspiring mentors, Profs.
Jacques Livage and Michel Che. This work was supported by the NSFC (21373004,
21573074 and 21533002), the CAS key laboratory of Low-Coal Conversion Science &
Engineering and JoRISS program. On the French side, the support came from the Joint
Research Institute for Science and Society founded by ECNU and ENS de Lyon, and by the
Auvergne-Rhônes-Alpes Region together with the French Ministry of European and Foreign
Affairs via an ARCUS-China grant. KZ thanks ENS de Lyon for a temporary position as
invited professor in France. LB also acknowledges the Chinese Government for the very
helpful Higher End Foreign Expert position at ECNU. Prof. Dongyuan Zhao from Fudan
University is acknowledged for his precious advices on the manuscript. We thank also Dr.
Pierre Avenas for guiding us on building the word “syntaxy”.
Received: ((will be filled in by the editorial staff))
Revised: ((will be filled in by the editorial staff))
Published online: ((will be filled in by the editorial staff))
References
[1]
a) S.-H. Wu, C.-Y. Mou, H.-P. Lin, Chem. Soc. Rev. 2013, 42, 3862; b) C. Sanchez, P.
Belleville, M. Popalld, L. Nicoleab, Chem. Soc. Rev. 2011, 40, 696; c) C. Sanchez, H.
Arribart, M. M. G. Gille, Nat. mater. 2005, 4, 277; d) C. Sanchez, C. Boissiere, S.
Cassaignon, C. Chaneac, O. Durupthy, M. Faustini, D. Grosso, C. Laberty-Robert, L.
Nicole, D. Portehault, F. Ribot, L. Rozes, C. Sassoye, Chem. Mater. 2014, 26, 221; e)
L. Han, S. Che, Chem. Soc. Rev. 2013, 42, 3740; f) C. Gao, S. Che, Adv. Funct. Mater.
2010, 20, 2750; g) C. Argyo, V. Weiss, C. Bräuchle, T. Bein, Chem. Mater. 2014, 26,
17
This article is protected by copyright. All rights reserved.

10.1002/chem.201704714
Chemistry - A European Journal
435; h) K. Möller, T. Bein, Chem. Mater. 2017, 29, 371; i) Y. Chen, H.-R. Chen, J.-L.
Shi, Acc. Chem. Res. 2014, 47, 125; j) S. Mann, D. D. Archibald, J. M. Didymus, T.
Douglas, B. R. Heywood, F. C. Meldrum, N. J. Reeves, Science 1993, 261, 1286.
a) M. Hildebrand, B. E. Volcani, W. Gassmann, J. I. Schroeder, Nature 1997, 385, 688;
b) K. Shimizu, J. Cha, G. D. Stucky, D. E. Morse, Proc. Natl. Acad. Sci. 1998, 95,
6234.
[2]
[3]
[4]
[5]
K. Zhang, L.-L. Xu, J.-G. Jiang, N. Calin, K.-F. Lam, S.-J. Zhang, H.-H. Wu, G.-D.
Wu, B. Albela, L. Bonneviot, P. Wu, J. Am. Chem. Soc. 2013, 135, 2427.
C. T. Kresge, M. E. Leonowicz, W. J. Roth, J. C. Vartuli, J. S. Beck, Nature 1992, 359,
710.
a) J. Livage, C. R. Palevol 2009, 8, 629; b) S. Chiruvolu, H. E. Warriner, E. Naranjo,
S. H. Idziak, J. O. Radler, R. J. Plano, J. A. Zasadzinski, C. R. Safinya, Science 1994,
266, 1222.
[6]
[7]
[8]
a) A. Firouzi, D. Kumar, L. Bull, T. Besier, P. Sieger, Q. Huo, S. Walker, J.
Zasadzinski, C. Glinka, J. Nicol, a. et, Science 1995, 267, 1138; b) Y. Waku, N.
Nakagawa, T. Wakamoto, H. Ohtsubo, K. Shimizu, Y. Kohtoku, Nature 1997, 389, 49.
a) X. Zhang, Y. Li, C. Cao, J. Mater. Chem. 2012, 22, 13918; b) R. Liu, Y. Shi, Y.
Wan, Y. Meng, F. Zhang, D. Gu, Z. Chen, B. Tu, D. Zhao, J. Am. Chem. Soc. 2006,
128, 11652.
a) C. E. Fowler, D. Khushalani, B. Lebeau, S. Mann, Adv. Mater. 2001, 13, 649; b)
Y.-S. Lin, N. Abadeer, K. R. Hurley, C. L. Haynes, J. Am. Chem. Soc. 2011, 133,
20444; c) D. Niu, Z. Liu, Y. Li, X. Luo, J. Zhang, J. Gong, J. Shi, Adv. Mater. 2014,
26, 4947; d) C. Urata, Y. Aoyama, A. Tonegawa, Y. Yamauchi, K. Kuroda, Chem.
Commun. 2009，5094; e) A. B. D. Nandiyanto, S.-G. Kim, F. Iskandar, K. Okuyama,
Microporous Mesoporous Mater. 2009, 120, 447; f) D. Zhao, J. Feng, Q. Huo, N.
Melosh, G. H. Fredrickson, B. F. Chmelka, G. D. Stucky, Science 1998, 279, 548.
D. Shen, J. Yang, X. Li, L. Zhou, R. Zhang, W. Li, L. Chen, R. Wang, F. Zhang, D.
Zhao, Nano Lett. 2014, 14, 923.
[9]
[10] a) Y. Fang, D. Gu, Y. Zou, Z. Wu, F. Li, R. Che, Y. Deng, B. Tu, D. Zhao, Angew.
Chem. Int. Ed. 2010, 49, 7987; b) C. Liang, Z. Li, S. Dai, Angew. Chem. Int. Ed. 2008,
47, 3696; c) A.-H. Lu, W.-C. Li, G.-P. Hao, B. Spliethoff, H.-J. Bongard, B. B.
Schaack, F. Schüth, Angew. Chem. Int. Ed. 2010, 49, 1615; d) J. Schuster, G. He, B.
Mandlmeier, T. Yim, K. T. Lee, T. Bein, L. F. Nazar, Angew. Chem. Int. Ed. 2012, 51,
3591; e) J. Liu, S. Z. Qiao, H. Liu, J. Chen, A. Orpe, D. Zhao, G. Q. Lu, Angew. Chem.
Int. Ed. 2011, 50, 5947; f) J. Liu, T. Yang, D.-W. Wang, G. Q. Lu, D. Zhao, S. Z. Qiao,
Nat. Commun. 2013, 4, 2798; g) K. Möller, J. Kobler, T. Bein, Adv. Funct. Mater.
2007, 17, 605; h) Z.-A. Qiao, B. Guo, A. J. Binder, J. Chen, G. M. Veith, S. Dai, Nano
Lett. 2013, 13, 207; i) J. Tang, J. Liu, C. Li, Y. Li, M. O. Tade, S. Dai, Y. Yamauchi,
Angew. Chem. Int. Ed. 2015, 54, 588; j) J. Zhang, Z.-A. Qiao, S. M. Mahurin, X. Jiang,
S.-H. Chai, H. Lu, K. Nelson, S. Dai, Angew. Chem. Int. Ed. 2015, 54, 4582; k) K.
Wang, L. Huang, S. Razzaque, S. Jin, B. Tan, Small 2016, 12, 3134; l) H. Tian, Z. Lin,
F. Xu, J. Zheng, X. Zhuang, Y. Mai, X. Feng, Small 2016, 12, 3155; m) Y. Fang, Y.
Lv, F. Gong, Z. Wu, X. Li, H. Zhu, L. Zhou, C. Yao, F. Zhang, G. Zheng, D. Zhao, J.
Am. Chem. Soc. 2015, 137, 2808; n) H. Zhang, O. Noonan, X. Huang, Y. Yang, C. Xu,
L. Zhou, C. Yu, ACS Nano 2016, 10, 4579; o) F. Xu, Z. Tang, S. Huang, L. Chen, Y.
Liang, W. Mai, H. Zhong, R. Fu, D. Wu, Nat. Commun. 2015, 6, 7221; p) Y.-X. Wang,
J. Yang, S.-L. Chou, H. K. Liu, W.-x. Zhang, D. Zhao, S. X. Dou, Nat. Commun. 2015,
6, 8689; q) T. Yang, H. Ling, J.-F. Lamonier, M. Jaroniec, J. Huang, M. J. Monteiro, J.
Liu, NPG Asia Mater. 2016, 8, e240; r) J. Liu, N. P. Wickramaratne, S. Z. Qiao, M.
Jaroniec, Nat. Mater. 2015, 14, 763.
[11] a) J. Hou, T. Cao, F. Idrees, C. Cao, Nanoscale 2016, 8, 451; b) S. Zou, X. Xu, Y. Zhu,
18
This article is protected by copyright. All rights reserved.

10.1002/chem.201704714
Chemistry - A European Journal
C. Cao, Microporous and Mesoporous Mate. 2017, 251, 114.
[12] C. Bernal, M. Mesa, M. Jaber, J. L. Guth, L. Sierra, Microporous Mesoporous Mater.
2012, 153, 217.
[13] R. Xing, N. Liu, Y. Liu, H. Wu, Y. Jiang, L. Chen, M. He, P. Wu, Adv. Funct. Mater.
2007, 17, 2455.
[14] a) J. G. Croissant, Y. Fatieiev, N. M. Khashab, Adv. Mater. 2017, 29, 1604634; b) L.
Zhou, Z. Zhuang, H. Zhao, M. Lin, D. Zhao, L. Mai, Adv. Mater. 2017, 1602914; c) C.
Chen, H. Wang, C. Han, J. Deng, J. Wang, M. Li, M. Tang, H. Jin, Y. Wang, J. Am.
Chem. Soc. 2017, 139, 2657; d) X. Du, S. Z. Qiao, Small 2015, 11, 392.
[15] Q. Huo, D. I. Margolese, U. Ciesla, P. Feng, T. E. Gier, P. Sieger, R. Leon, P. M.
Petroff, F. Schuth, G. D. Stucky, Nature 1994, 368, 317.
[16] G. M. Whitesides, B. Grzybowski, Science 2002, 295, 2418.
[17] a) S. Jun, S. H. Joo, R. Ryoo, M. Kruk, M. Jaroniec, Z. Liu, T. Ohsuna, O. Terasaki, J.
Am. Chem. Soc. 2000, 122, 10712; b) S. Inagaki, Y. Fukushima, K. Kuroda, J. Am.
Chem. Soc., Chem. commun. 1993, 680; c) G. S. Attard, J. C. Glyde, C. G. Goltner,
Nature 1995, 378, 366.
Figure 1. Reaction scheme, synoptic of sample nomenclature, SEM and TEM images.
Scheme (top left), nomenclature (top right) SEM images of the carbonized hybrid
nanospheres CS-MNS-x (a to c), direct TEM images of yin and yang single phases C- or S-
MNS-x (d-i) with insets for particle size distribution (PSD).
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Figure 2. Inverted contrast TEM images of nanospheres adopting different topologies
and pore arrays: (a to f) C- or S-MNS-x samples and (g to i) S-MNS from ref.3;
nomenclature provided in Table 1 and explained in SI.
Figure 3. EDX elemental analysis. Mappings of O (blue), Si (yellow) and C (red) of CS-
MNS-x yin and yang hybrids (x = 1, 2 and 3 for left, middle and right column, respectively);
yellow arrows pointing a location where the carbon nanophase wraps up a silica dendrite;
Rows 4 and 5, superposition of O + Si and Si + C mappings.
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Figure 4. Pore size distribution (PSD), Reaction scheme and Catalytic activity. (A) X-
MNS-1 and b) X-MNS-2 (BJH model), B top) reaction scheme of m-cresol (m-C) with tert-
butyl-alcohol (t-BA) converted into 2-tert-butyl-5-methylphenol (2-t-BMP) or 4-tert-butyl-5-
methylphenol (4-t-BMP), B bottom) catalytic conversion (black bar) and selectivity (red bar)
of various silica and carbon nanospheres after functionalization by sulfonic acid groups
including zeolites ZSM-5, USY-1, dealuminated USY-2 and USY-3 and C) specific micelle
templated distance between nanophases (color code in Fig. 5).
Figure 5. Key mechanism steps, specific spacings and derivatized nanophases: (left
column) main steps of syntaxic phase entanglement, and (right set of five windows)
derivatized syntaxic nanophases; micelles (blue), silica phase (yellow), polymer (purple-red)
and carbon (black) phases.
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Table 1. Morphology descriptors for topology and pore array.
Topology
Code
Pore array
Code
Uniform
U
disordered
d
core-shell
CS
CSC
Hw
-
center radial
dendritic
stellar
r
core-shell-corona
De
St
Rb
hollowa
-
raspberry
a)described in the triphasic resol-surfactant-silica system by other groups in refs. 7a and 11.
Table 2. Textural and structural characteristics of X-MNS-x nanospheres.
b)
c)
d)
Samplea)
SBET
Vtotal
DBJH
PSDe)
(nm)
Morphology:
(m2/g)
(ml/g)
(nm)
topology & pore array f)
PS-MSNS-1
CS-MSNS-1
*CS-MSNS-1
S-MSNS-1
495
321
221
577
806
83
0.57
0.37
0.56
1.65
1.46
0.12
0.31
0.35
1.11
1.61
0.07
0.32
0.44
0.70
1.51
5 (2-10)
4 (2-8)
-
U-Pv/De
U-Pv/De
U-Pv/De
U-De
-
12 (6-25)
-
14 (8-20)
140 ± 20
C-MSNS-1
PS-MSNS-2
CS-MSNS-2
*CS-MSNS-2
S-MSNS-2
14 (8-20)
135 ± 15
U-Pv
9 (5-20)
-
CSC-drr/drr
CSC-drr/drr
CSC-drr/drr
CSC-drr
CSC-drr
CS-dr/rr
CS-dr/rr
CS-dr/rr
CS-rr
374
291
340
747
68
9 (5-20)
-
14 (9-30)
-
23 (15-40)
19 (9 -25)
6 (2-10) & ~ 26
3 (2-7) & ~ 26
24 (12-35)
380 ± 25
C-MSNS-2
PS-MSNS-3
CS-MSNS-3
*CS-MSNS-3
S-MSNS-3
375 ± 30
-
-
-
449
368
513
739
10 (6-16) & ~ 42 480 ± 40
9 (5-13) & 22 440 ± 38
C-MSNS-3
CS-dr
a)P, C, S phases, = Polymer, Carbon, Silica and, x = 1-3, 1 = TEAH3, 2 = AHMPD and 3 =
NH3∙H2O, respectively, *C for carbonization in the presence of the surfactant; b) specific
surface area measured from N2 physisorption isotherm (Fig. S6), and surface per volume unity
in m2/cm3 or volumetric surface area calculated from bulk densities of amorphous silica and
resol-formaldehyde of 2.3 and 1.25 g/cm3, respectively; c) total pore volume measured at P/Po
= 0.99; d) pore diameter calculated at the maximum of the distribution using the adsorption
branch and the BJH theoretical model, in parenthesis range of the distribution estimated from
half height of the distribution and, secondary pore size distribution indicated after the symbol
“~” when detected; e) particle size distribution (PSD) from TEM; f) when both yin and yang
nanophases are still entangled, the pore array is indicated in the order of the phases given in
the sample name (here P or C provided before S).
22
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