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Porosity and Surface Properites of SBA-15 with Grafted PNIPAAM: A Water Sorption Calorimetry Study

Reichhardt, Nina LU ; Nylander, Tommy LU ; Klosgen, B.; Alfredsson, Viveka LU and Kocherbitov, V. (2011) In Langmuir 27(22). p.13838-13846
Abstract
Mesoporous silica SBA-15 was modified in a three-step process to obtain a material with poly-N-isopropylacrylamide (PNIPAAM) grafted onto the inner pore surface. Water sorption calorimetry was implemented to characterize the materials obtained after each step regarding the porosity and surface properties. The modification process was carried out by (i) increasing the number of surface silanol groups, (ii) grafting 1-(trichlorosilyl)-2-(m-/p-(chloromethylphenyl) ethane, acting as an anchor for (iii) the polymerization of N-isopropylacrylamide. Water sorption isotherms and the enthalpy of hydration are presented. Pore size distributions were calculated on the basis of the water sorption isotherms by applying the BJH model. Complementary... (More)
Mesoporous silica SBA-15 was modified in a three-step process to obtain a material with poly-N-isopropylacrylamide (PNIPAAM) grafted onto the inner pore surface. Water sorption calorimetry was implemented to characterize the materials obtained after each step regarding the porosity and surface properties. The modification process was carried out by (i) increasing the number of surface silanol groups, (ii) grafting 1-(trichlorosilyl)-2-(m-/p-(chloromethylphenyl) ethane, acting as an anchor for (iii) the polymerization of N-isopropylacrylamide. Water sorption isotherms and the enthalpy of hydration are presented. Pore size distributions were calculated on the basis of the water sorption isotherms by applying the BJH model. Complementary measurements with nitrogen sorption and small-angle X-ray diffraction are presented. The increase in the number of surface silanol groups occurs mainly in the intrawall pores, the anchor is mainly located in the intrawall pores, and the intrawall pore volume is absent after the surface grafting of PNIPAAM. Hence, PNIPAAM seals off the intrawall pores. Water sorption isotherms directly detect the presence of intrawall porosity. Pore size distributions can be calculated from the isotherms. Furthermore, the technique provides information regarding the hydration capability (i.e., wettability of different chemical surfaces) and thermodynamic information. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
27
issue
22
pages
13838 - 13846
publisher
The American Chemical Society
external identifiers
  • wos:000296598300054
  • scopus:80755142916
ISSN
0743-7463
DOI
10.1021/la203093u
language
English
LU publication?
yes
id
36721628-06a6-43e1-941f-5e9ba7c4adc7 (old id 2254362)
date added to LUP
2011-12-20 09:49:38
date last changed
2017-01-01 04:02:09
@article{36721628-06a6-43e1-941f-5e9ba7c4adc7,
  abstract     = {Mesoporous silica SBA-15 was modified in a three-step process to obtain a material with poly-N-isopropylacrylamide (PNIPAAM) grafted onto the inner pore surface. Water sorption calorimetry was implemented to characterize the materials obtained after each step regarding the porosity and surface properties. The modification process was carried out by (i) increasing the number of surface silanol groups, (ii) grafting 1-(trichlorosilyl)-2-(m-/p-(chloromethylphenyl) ethane, acting as an anchor for (iii) the polymerization of N-isopropylacrylamide. Water sorption isotherms and the enthalpy of hydration are presented. Pore size distributions were calculated on the basis of the water sorption isotherms by applying the BJH model. Complementary measurements with nitrogen sorption and small-angle X-ray diffraction are presented. The increase in the number of surface silanol groups occurs mainly in the intrawall pores, the anchor is mainly located in the intrawall pores, and the intrawall pore volume is absent after the surface grafting of PNIPAAM. Hence, PNIPAAM seals off the intrawall pores. Water sorption isotherms directly detect the presence of intrawall porosity. Pore size distributions can be calculated from the isotherms. Furthermore, the technique provides information regarding the hydration capability (i.e., wettability of different chemical surfaces) and thermodynamic information.},
  author       = {Reichhardt, Nina and Nylander, Tommy and Klosgen, B. and Alfredsson, Viveka and Kocherbitov, V.},
  issn         = {0743-7463},
  language     = {eng},
  number       = {22},
  pages        = {13838--13846},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Porosity and Surface Properites of SBA-15 with Grafted PNIPAAM: A Water Sorption Calorimetry Study},
  url          = {http://dx.doi.org/10.1021/la203093u},
  volume       = {27},
  year         = {2011},
}