Overview

We focus on the dynamics of nano-structured polymers. More specifically, we are interested in:

Structure and dynamics of glass formers in bulk and under confinement
Fabrication and characterization of nanostructured materials
Stability and Instability of the polymer nanostructures
Inelastic light/neutron scattering spectroscopy
Nanoimprint Lithography

Our research is supported by National Science Foundation, ACS-PRF, MAST Center and the University of Colorado. Detailed descriptions of on-going projects can be found in the Research page. We are an interdisciplinary group interested in academic collaborations.

News

03/15/2013 - Zhen passed his PhD thesis defense!

Congratulations to Zhen for passing his PhD thesis defense! Zhen's thesis, entitled "Demixing of Polymers Under Nanoimprinting Process", was presented to a five-member thesis committee; he successfully passed the scrutiny of the committee. In Zhen's doctoral research, he studied the influence of substrate surface energy on the morphological evolution of planar polymer blend films and topographically patterned films. He demontrated that high-fidelity pattern replication can be achieved on demixed blend films using nanoimprint lithography, which can then evolve into a wide range of unique and hierachical micro or nanostructures. He has authored a total of 7 research papers published on leading polymer and nanoscience journals. He is also the recipient of the 2010-2012 Teets Family Fellowship (2 out of all graduate students in engineering college). Congratulations, Dr. Wang!

03/12/2013 - Zheng's proposal to the Beverly Sears Graduate Student Grant won a named award!

Zheng's proposal of "Developing a controllable and high-throughput methodology for engineering well-aligned carbon nanofibers" has been approved by the Beverly Sears Graduate Student Grant program and ranked top 5% among all submissions across the campus. Zheng has also been selected to receive the Friends of the Graduate School Named Award, in the honor of private donors who support the research and creative goals of graduate students. Only the highest ranked proposals are considered for the small number of named awards, and recipients receive the full amount of their request.

02/18/2013 - Liang's paper has been accepted to be published on Soft Matter!

In this report titled "Photocrosslinking-induced Phase Separation in Evaporative Solvents: Formation of Skin Layers and Microspheres", we investigated the structure formation of films obtained via photocrosslinking of precursors during the evaporation of solvents. The film structure after processing is highly hierarchical, featuring a skin layer on top of a layer of microspheres formed via reaction induced phase separation mechanism. More importantly, the feature size of structures can be readily achieved by changing processing parameters including N2 flow rate, UV intensity and precursor concentrations.

02/08/2013 - Zheng's paper has been published on Langmuir

We studied the "influence of substrate confinement on the phase-correlation in the capillary breakup of arrays of patterned polymer stripes". For the two extreme cases of viscosity ratios we investigated, in-phase breakup of strongly confined immiscible polymer stripes was always observed, regardless of the specific geometry.This was because the rigid substrate suppressed undulations on the polymer stripes from being developed perpendicularly to the substrate and, therefore, lateral undulations between neighboring stripes became strongly coupled.

01/09/2013 - Maruf's paper is now published on Journal of Membrane Science!

In this study titled "Use of nanoimprinted surface patterns to mitigate colloidal deposition on ultrafiltration membranes", we demonstrate that submicron patterns can be successfully imprinted onto a commercial polysulfone ultrafiltration membrane surface using nanoimprint lithography (NIL) without sacrificing much of its permeability properties. The presence of these patterns led to significantly improved deposition resistance during filtration of colloidal silica particle suspensions. These results suggest a promising chemical-free manufacturing route to achieve antifouling properties for commercial ultrafiltration membrane.