Correction pubs.acs.org/macroletters
Correction to Accessing Siloxane Functionalized Polynorbornenes via Vinyl-Addition Polymerization for CO2 Separation Membranes Kevin R. Gmernicki, Eunice Hong, Christopher R. Maroon, Shannon M. Mahurin, Alexei P. Sokolov, Tomonori Saito, and Brian K. Long*
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ACS Macro Lett. 2016, 5 (7), 879−883. DOI: 10.1021/acsmacrolett.6b00435 n our recent letter “Accessing Siloxane Functionalized Polynorbornenes via Vinyl-Addition Polymerization for CO2 Separation Membranes” (ACS Macro Lett. 2016, 5, 879−883), we miscalculated the values for density and fractional free volume (FFV) of polymers 3c, 3d, and 3e (Table 3).1 This error arose as the densities of those polymers were measured using Archimedes Principle in MeOH, and during the final calculations an incorrect value for the density of methanol was propagated in our spreadsheet. Because the calculation of FFV is based upon polymer density, the same error propagated to those values as well. This error does not change the conclusions of the article; however, the values in the original article are not representative of the polymers’ actual densities and FFV. The corrected values are shown in Table 1 below. Furthermore, a portion of the paragraph describing those values (portion of first paragraph, page 882) should now read as follows: “To support this hypothesis, densities of polymers 3c−e were measured using Archimedes Principle, which yielded values of 1.027−1.081 g/cm3 (Table 3). These densities are greater than poly(5-trimethylsilyl-2-norbornene) (density = 0.883 g/mL) and support that PNBs bearing siloxane moieties may indeed pack more tightly than polymers bearing simple silanes. Furthermore, the fractional free volume (FFV) of polymers 3c−e were estimated to range from 0.108 to 0.139, as calculated using the Bondi Method (Table 3).2 These values are notably smaller than the FFV reported for poly(5-trimethylsilyl-2norbornene) (FFV = 0.275)3 and further support the hypothesis that the observed decrease in CO2 permeability for polymers 3c−e may be due to increased chain packing within their thinfilm matrices. Lastly, ...”
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REFERENCES
(1) Gmernicki, K. R.; Hong, E.; Maroon, C. R.; Mahurin, S. M.; Sokolov, A. P.; Saito, T.; Long, B. K. ACS Macro Lett. 2016, 5, 879−883. (2) Bondi, A. J. Phys. Chem. 1964, 68, 441−451. (3) Finkelshtein, E. S.; Makovetskii, K. L.; Gringolts, M. L.; Rogan, Y. V.; Golenko, T. G.; Starannikova, L. E.; Yampolskii, Y. P.; Shantarovich, V. P.; Suzuki, T. Macromolecules 2006, 39, 7022−7029. (4) Klug, H. P.; Alexander, L. E. X-Ray Diffraction Procedures for Polycrystalline and Amorphous Materials., 2nd ed; Wiley-Interscience, 1974.
Table 1. Permeability and Ideal Selectivity of Polymers 3c−e d spacing,c Å
Pd (Barrer)
entry
polymer
densitya (g/cm3)
FFVb
(2θ)1,c deg
(2θ)2,c deg
(dB/dic)1
(dB/dic)2
CO2
N2
α (CO2/N2)
1 2 3
3c 3d 3e
1.081 (±0.009) 1.089 (±0.012) 1.027 (±0.012)
0.131 (±0.007) 0.108 (±0.010) 0.139 (±0.010)
6.2 6.5 7.1
13.7 14.2 15.3
14.2/17.4 13.4/16.3 12.4/15.2
6.5/7.9 6.0/7.3 5.8/7.0
936.6 (±14.9) 474.2 (±12.0) 470.7 (±15.2)
57.3 (±2.3) 24.5 (±0.3) 24.9 (±1.1)
16.4 (±0.4) 19.3 (±1.1) 18.9 (±1.5)
a Determined using Archimedes Principle in MeOH at 22 °C. bEstimated using the Bondi method. cDetermined using wide-angle X-ray diffraction, dB is calculated using Bragg’s Law (dB = λ/(2 sin θ), dic is calculated using a correction factor as described in the literature (dic = 1.22dB).4 d Permeability values of free-standing polymer films were obtained using the constant-volume variable-pressure gas flux method as detailed in the Supporting Information.
Received: December 16, 2016
© XXXX American Chemical Society
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DOI: 10.1021/acsmacrolett.6b00956 ACS Macro Lett. 2017, 6, 41−41
