Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


case1301326975.pdf (14.36 MB)

ETD Abstract Container

Abstract Header

COLLOIDAL INTERACTIONS AND STABILITY IN PROCESSING, FORMATION AND PROPERTIES OF INORGANIC-ORGANIC NANOCOMPOSITES

Alhassan, Saeed M.
http://rave.ohiolink.edu/etdc/view?acc_num=case1301326975

Abstract Details

2011, Doctor of Philosophy, Case Western Reserve University, Chemical Engineering.
Colloidal interactions are important in understanding and controlling the stability of colloids since these systems are usually far from thermodynamic equilibrium. Colloidal interactions in liquid based colloids are either attractive or repulsive. The Derjaguin and Landau, Verwey and Overbeek theory (DLVO) of colloidal stability assumes that the total potential interaction is a sum of attractive and repulsive forces. The additivity assumption does not hold for all colloidal systems, especially for colloids stabilized or flocculated by the presence of polymer in solution. However, the qualitative success of the theory is used to explain the observed phenomena herein. In the first part of the project, the effects of electrolyte and polymer addition on formation and mechanical properties of clay aerogels were explored. Incoherent aerogels were formed in samples with low polymer loading and low electrolyte concentration but all other loadings, coherent aerogels were produced. The mechanical properties of aerogels have a power law dependence on relative and bulk density with high exponent values. The high exponent values are attributed to the aerogel layered structure, anisotropy and enhanced exfoliation with polymer addition. In the second part of the project, the exfoliation of graphene in water was achieved using turbulent mixing at ambient conditions. Turbulent mixing was used as mean to overcome van der Waals forces between graphene layers in graphite and laponite was used to arrest exfoliated graphene from aggregation. The method can exfoliate graphite down to bilayer graphene as evident from Raman spectra, transmission electron microscopy (TEM) and x-ray diffraction. The laponite colloidal Wigner glass is a suitable medium for studying, not only graphene, but also other nanoparticles and biological macromolecules. In the third part of the study, main chain benzoxazine polymer was used to synthesize aerogels and nanocomposites. The aerogel was produced through thermally induced phase separation method. The mechanical properties of these aerogels have power law dependence on density with exponent values that are comparable to those reported for silica aerogels and clay aerogels. Graphene oxide polybenzoxazine nanocomposites were made via solution casting. Surprisingly, the thermal properties of these nanocomposties decrease due to reactivity of graphene oxide at the same processing window of polybenzoxazine.
Syed Qutubuddin, PhD (Advisor)
David Schiraldi, PhD (Advisor)
J. Adin Mann Jr., PhD (Committee Member)
R. Mohan Sankaran, PhD (Committee Member)
162 p.
Chemical Engineering
clay; graphene; graphene oxide; aerogel; laponite; turbulence; exfoliation; colloidal interactions; DLVO theory; colloidal stability; nanocomposites

Recommended Citations

Citations

  • Alhassan, S. M. (2011). COLLOIDAL INTERACTIONS AND STABILITY IN PROCESSING, FORMATION AND PROPERTIES OF INORGANIC-ORGANIC NANOCOMPOSITES [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1301326975

    APA Style (7th edition)

  • Alhassan, Saeed. COLLOIDAL INTERACTIONS AND STABILITY IN PROCESSING, FORMATION AND PROPERTIES OF INORGANIC-ORGANIC NANOCOMPOSITES. 2011. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1301326975.

    MLA Style (8th edition)

  • Alhassan, Saeed. "COLLOIDAL INTERACTIONS AND STABILITY IN PROCESSING, FORMATION AND PROPERTIES OF INORGANIC-ORGANIC NANOCOMPOSITES." Doctoral dissertation, Case Western Reserve University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1301326975

    Chicago Manual of Style (17th edition)

case1301326975
1,461
© 2011, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.