skip to main content


Search for: All records

Creators/Authors contains: "Imran, Omar Q."

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Lyotropic liquid crystals (LLCs) have drawn attention in numerous technical fields as they feature a variety of nanometer-scale structures, processability, and diverse chemical functionality. However, they suffer from poor mechanical properties and thermal stability. Polymerization in LLCs, referred to as LLC templating, is an effective approach to overcome this issue. While the templating approach results in robust mechanical, physical, and thermal properties, retention of the parent LLC structure after polymerization has been a major concern in the field. Therefore, there have been several efforts to introduce new materials and techniques to preserve the native LLC nanostructure after polymerization. In this review, we survey the efforts put in this area along with the applications of the obtained materials from LLC templating, after providing a brief introduction of LLC structures. Moreover, polymerization kinetics in different LLC structures, as a key player in the structure retention, are analyzed. Furthermore, we discuss the outlook of the field and available opportunities. 
    more » « less
  2. A single-head/single-tail surfactant with a polymerizable group at each end is presented as a new simplified motif for intrinsically cross-linkable, gyroid-phase lyotropic mesogens. The resulting nanoporous polymer networks exhibit excellent structural stability in various solvents and are capable of molecular size discrimination. 
    more » « less
  3. Abstract

    The preparation of thin films of nanostructured functional materials is a critical step in a diverse array of applications ranging from photonics to separation science. New thin‐film fabrication methods are sought to harness the emerging potential of self‐assembled nanostructured materials as next‐generation membranes. Here, the authors show that nanometer‐scale control over the thickness of self‐assembled mesophases can be enacted by directional photopolymerization in the presence of highly photo‐attenuating molecular species. Metrology reveals average film growth rates below ten nanometers per second, indicating that high‐resolution fabrication is possible with this approach. The trends in experimental data are reproduced well in numerical simulations of mean‐field frontal photopolymerization modeled in a highly photo‐attenuating and photo‐bleaching medium. These simulation results connect the experimentally observed nanometer‐scale control of film growth to the strong photo‐attenuating nature of the mesophase, which originates from its high‐aromatic‐ring content. Water permeability measurements conducted on the fabricated thin films show the expected linear scaling of permeability with film thickness. Film permeabilities compare favorably with current state‐of‐the‐art nanofiltration and reverse osmosis membranes, suggesting that the current approach may be utilized to prepare new nanoporous membranes for such applications.

     
    more » « less