Limits...
A combination of hard and soft templating for the fabrication of silica hollow microcoils with nanostructured walls.

Rodriguez-Abreu C, Vilanova N, Solans C, Ujihara M, Imae T, López-Quintela A, Motojima S - Nanoscale Res Lett (2011)

Bottom Line: Moreover, they have mesoporous walls (pore size ≈ 3 nm) with some domains where pores are ordered in a hexagonal array, originated from surfactant micelles.The obtained silica microcoils also show preferential adsorption of cationic fluorescent dyes.A mechanism for the formation of silica microcoils is proposed.

View Article: PubMed Central - HTML - PubMed

Affiliation: International Iberian Nanotechnology Laboratory (INL), Av, Mestre José Veiga, Braga, 4715-310, Portugal. crodriguez@inl.int.

ABSTRACT
Hollow silica microcoils have been prepared by using functionalized carbon microcoils as hard templates and surfactant or amphiphilic dye aggregates as soft templates. The obtained materials have been characterized by electron and optical microscopy, nitrogen sorption and small angle X-ray scattering. The obtained hollow microcoils resemble the original hard templates in shape and size. Moreover, they have mesoporous walls (pore size ≈ 3 nm) with some domains where pores are ordered in a hexagonal array, originated from surfactant micelles. The obtained silica microcoils also show preferential adsorption of cationic fluorescent dyes. A mechanism for the formation of silica microcoils is proposed.

No MeSH data available.


Related in: MedlinePlus

TEM images of different sections of silica hollow microcoils. The initial weight ratios for the silica coating process were CTAB/NH3(aq.)/CMC-COOH/TEOS = 13.7/69.4/2.0/14.9.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211418&req=5

Figure 3: TEM images of different sections of silica hollow microcoils. The initial weight ratios for the silica coating process were CTAB/NH3(aq.)/CMC-COOH/TEOS = 13.7/69.4/2.0/14.9.

Mentions: TEM images of silica hollow microcoils are presented in Figure 3. The photographs at low magnification show unambiguously the hollow nature of the specimens; the very thin silica walls allow the transmission of the electron beam. The fine structure of the walls can be imaged at higher magnification. Arranged channels of about 3-nm width were observed in some sections of the microcoil walls. The cross section of those channels is circular, namely, the walls contain cylindrical mesopores, some of which ordered in a hexagonal fashion. However, it should be pointed out that mesopores with disordered domains (worm-hole morphology) also exist in the microcoil walls. The existence of mesopores was confirmed by nitrogen sorption experiments, which gave a relatively narrow pore size distribution with a maximum at 2.3 nm, in agreement with TEM observations (see Figure S1 in Additional file 1). Samples of silica coils were also analyzed by SAXS. Patterns showed a strong peak corresponding to a Bragg spacing d of 3.8 nm (see Figure S2 in Additional file 1); the lattice parameter for a hexagonal array (a = 2d/√3) was calculated as 4.4 nm, which is similar to that of MCM-41 silica [20].


A combination of hard and soft templating for the fabrication of silica hollow microcoils with nanostructured walls.

Rodriguez-Abreu C, Vilanova N, Solans C, Ujihara M, Imae T, López-Quintela A, Motojima S - Nanoscale Res Lett (2011)

TEM images of different sections of silica hollow microcoils. The initial weight ratios for the silica coating process were CTAB/NH3(aq.)/CMC-COOH/TEOS = 13.7/69.4/2.0/14.9.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211418&req=5

Figure 3: TEM images of different sections of silica hollow microcoils. The initial weight ratios for the silica coating process were CTAB/NH3(aq.)/CMC-COOH/TEOS = 13.7/69.4/2.0/14.9.
Mentions: TEM images of silica hollow microcoils are presented in Figure 3. The photographs at low magnification show unambiguously the hollow nature of the specimens; the very thin silica walls allow the transmission of the electron beam. The fine structure of the walls can be imaged at higher magnification. Arranged channels of about 3-nm width were observed in some sections of the microcoil walls. The cross section of those channels is circular, namely, the walls contain cylindrical mesopores, some of which ordered in a hexagonal fashion. However, it should be pointed out that mesopores with disordered domains (worm-hole morphology) also exist in the microcoil walls. The existence of mesopores was confirmed by nitrogen sorption experiments, which gave a relatively narrow pore size distribution with a maximum at 2.3 nm, in agreement with TEM observations (see Figure S1 in Additional file 1). Samples of silica coils were also analyzed by SAXS. Patterns showed a strong peak corresponding to a Bragg spacing d of 3.8 nm (see Figure S2 in Additional file 1); the lattice parameter for a hexagonal array (a = 2d/√3) was calculated as 4.4 nm, which is similar to that of MCM-41 silica [20].

Bottom Line: Moreover, they have mesoporous walls (pore size ≈ 3 nm) with some domains where pores are ordered in a hexagonal array, originated from surfactant micelles.The obtained silica microcoils also show preferential adsorption of cationic fluorescent dyes.A mechanism for the formation of silica microcoils is proposed.

View Article: PubMed Central - HTML - PubMed

Affiliation: International Iberian Nanotechnology Laboratory (INL), Av, Mestre José Veiga, Braga, 4715-310, Portugal. crodriguez@inl.int.

ABSTRACT
Hollow silica microcoils have been prepared by using functionalized carbon microcoils as hard templates and surfactant or amphiphilic dye aggregates as soft templates. The obtained materials have been characterized by electron and optical microscopy, nitrogen sorption and small angle X-ray scattering. The obtained hollow microcoils resemble the original hard templates in shape and size. Moreover, they have mesoporous walls (pore size ≈ 3 nm) with some domains where pores are ordered in a hexagonal array, originated from surfactant micelles. The obtained silica microcoils also show preferential adsorption of cationic fluorescent dyes. A mechanism for the formation of silica microcoils is proposed.

No MeSH data available.


Related in: MedlinePlus