Supplementary Material
Formation and characterization of perfluorocyclobutyl polymer thin films
Jinxiang Zhoua, Jianyong Jinb‡, Adam T. Haldemanb, Earl H. Wagenerb, Scott M. Hussona,*
a
Department of Chemical and Biomolecular Engineering and Center for Advanced Engineering
Fibers and Films, Clemson University, 127 Earle Hall, Clemson, SC 29634, USA
b
Tetramer Technologies, LLC, 657 South Mechanic Street, Pendleton, SC 29670, USA
‡
Current address: School of Chemical Sciences, The University of Auckland, Tamaki Innovation
Campus, 261 Morrin Road, St. Johns, Auckland Private Bag 92019, Auckland 1142, New
Zealand
*Correspondence: shusson@clemson.edu; Tel.: +1 (864) 656-4502; Fax: +1 (864) 656-0784
This Supplementary Material document contains (1) viscosity data for solutions of
perfluorocyclobutyl (PFCB-BPVE) polymer in chloroform and tetrahydrofuran, (2) refractive
index data for PFCB-BPVE thin films, (3) TEM image of composite membrane that enables
direct comparison of PFCB layer thickness to that on a silicon wafer using the same coating
conditions.
Figures S1 and S2 show absolute viscosities of PFCB solutions measured using a cup and bob
rheometer. PFCB/chloroform and PFCB/THF solutions exhibited slight shear thickening over the
measured shear rate range.
Figure S3 shows refractive index values for PFCB thin films that vary in film thickness. A
significant difference was found between RI values measured at the two endpoint incidence
angles of 56° and 80°, indicates anisotropic properties of PFCB thin films below about 50 nm.
Figure S4 shows a TEM image of a PFCB thin-film composite membrane cross section. The dark
region represents the PFCB layer, which has a thickness of about 100 nm. The solution used for
coating was 1.5 wt% PFCB in chloroform, and coating was done at a dip coating withdrawal
speed of 210 mm/min. By comparison, the PFCB film thickness measured on silicon wafer using
the exact same conditions was measured by ellipsometry to be 91 ± 5 nm. The uncertainty
represents standard deviation among five measurement points.
Figure S1. Viscosity measurements for PFCB/chloroform solutions. Triangles, squares and
diamonds represent 1.00 wt %, 0.50 wt % and 0.25 wt % bulk PFCB concentrations.
Figure S2. Viscosity measurements for PFCB/THF solutions. Triangles, squares and diamonds
represent 1.00 wt %, 0.50 wt % and 0.25 wt % bulk PFCB concentrations, respectively.
Figure S3. Refractive index of PFCB thin films measured by ellipsometry at 80° (squares) and
56° (diamonds).
Figure S4. TEM image of a PFCB thin-film composite membrane cross section. The dark region
represents the PFCB layer, which has a thickness of about 100 nm.