Nanostructure Charaterization 

Our research group was instrumental in the development of advanced X-ray scattering technologies to probe a wide range of polymer problems at length scale ranging from Angstroms to sub-microns in real time. Hsiao was also responsible for the development of the first scattering beamline (X27C) dedicated to polymer research at toe National Synchrotron Light Source (NSLS) in Brookhaven National Laboratory, where more than 1000 researchers from over 100 research Institutes have carried out experiments In his beamline. 

Polymer Crystallization

Scanning electron micrographs of a solvent-extracted sheared polyethylene (PE) blend revealed, for the first time, an unexpected shish-kebab structure with multiple shish. The blend contained 2 wt % of crystallizing ultrahigh molecular weight polyethylene (UHMWPE) and 98 wt % of noncrystallizing PE matrix. The formation of multiple shish was attributed to the coil-stretch transition occurring in sections of UHMWPE chains. Synchrotron x-ray data provided clear evidence of the hypothesis that multiple shish originate from stretched chain sections and kebabs originate from coiled chain sections, following a diffusion-controlled crystallization process.

Synthetic and Natural Nanocomposite

Combined small-angle x-ray scattering and transmission electron microscopy studies of intramuscular fish bone (shad and herring) indicate that the lateral packing of nanoscale calcium-phosphate crystals in collagen fibrils can be represented by irregular stacks of platelet-shaped crystals, intercalated with organic layers of collagen molecules. The scattering intensity distribution in this system can be described by a modified Zernike-Prins model, taking preferred orientation effects into account. Using the model, the diffuse fan-shaped small-angle x-ray scattering intensity profile, dominating the equatorial region of the scattering pattern, could be quantitatively analyzed as a function of the degree of mineralization. 

Nanofiber Technology

Nanostructured fibrous materials have been made more readily available in large part owing to recent advances in electrospinning and related technologies, including the use of electrostatic or gas-blowing forces as well as a combination of both forces. The nonwoven structure has unique features, including interconnected pores and a very large surface-to-volume ratio, which enable such nanofibrous scaffolds to have many biomedical and industrial applications. The chemical composition of electrospun membranes can be adjusted through the use of different polymers, polymer blends, or nanocomposites made of organic or inorganic materials.

Biomedical Applications​

The structural and functional effects of fine-textured matrices with sub-micron features on the growth of cardiac myocytes were examined. Electrospinning was used to fabricate biodegradable non-woven poly(lactide)- and poly(glycolide)-based (PLGA) scaffolds for cardiac tissue engineering applications. Post-processing was applied to achieve macro-scale fiber orientation (anisotropy). In vitro studies confirmed a dose–response effect of the poly(glycolide) concentration on the degradation rate and the pH value changes. Different formulations were examined to assess scaffold effects on cell attachment, structure and function. Primary cardiomyocytes (CMs) were cultured on the electrospun scaffolds to form tissue-like constructs

Water Purificaion Application

Ultrafine polysaccharide nanofibers (i.e., cellulose and chitin) with 5 -10 nm diameters were employed as barrier layers in a new class of thin-film nanofibrous composite (TFNC) membranes for water purification. In addition to concentration, the viscosity of the polysaccharide nanofiber coating suspension was also found to be affected by the pH value and ionic strength. When compared with two commercial UF membranes (PAN10 and PAN400), 10-fold higher permeation flux with above 99.5% rejection ratio were achieved by using ultrafine cellulose nanofibers-based TFNC membranes for ultrafiltration of oil/water emulsions.