Sorption and swelling of block copolymers in the presence of supercritical fluid carbon dioxide

Zhang, Yi; Gangwani, Kishore K; Lemert, Richard M.

doi:10.1016/s0896-8446(97)00031-4

Cited by 136 publications

(170 citation statements)

References 50 publications

Supporting

Mentioning

155

Contrasting

Unclassified

Order By: Relevance

“…37 Regardless of the film thickness, increased disparity between the CO2-PS and CO2-PEO interactions corresponds to a larger effective interaction parameter (χeff), leading to phase separation. The solubility of CO2 in both the PS and PEO homopolymers has previously been reported to decrease with increasing temperature and increases with increasing pressure, 36,38 which is consistent with the fact that the interactions between polymers and CO2 become less favourable with increasing temperature, lowering the probability of phase separation. These previous studies also explains why lower temperatures (< 50 o C) are more suitable to achieve phase separation at a constant pressure.…”

Section: Role Of Scf On Microphase Separationsupporting

confidence: 77%

“…The solubility of a block copolymer generally falls between that of its two homopolymers. 29 As various authors have reported that the solubility of scCO2 of polymers is only significantly influenced by pressure and temperature and almost independent of the molar mass of PS and PEO, 31,[35][36] it seems unlikely that the cause of enhanced phase separation is related to a swelling effect leading to greater free volume and increased chain mobility.…”

Section: Microphase Separation Of Higher Molecular Weight Bcpmentioning

confidence: 99%

“…32 The sorption of scCO2 in PEO is found to be in between 20-25 wt%, which is larger than that of PS (5-6 wt%) at a pressure of 100 bar. 36,[38][39] Thus, enhanced swelling of the PEO domain is expected compared to the PS block. CO2 also interacts favourably with the hydroxyl groups on the SiOx/Si substrate, with the effect of screening the segmental interactions of the polymer with the substrate.…”

Section: Role Of Scf On Microphase Separationmentioning

confidence: 99%

See 2 more Smart Citations

Nanophase separation and structural evolution of block copolymer films: A “green” and “clean” supercritical fluid approach

et al. 2014

View full text Add to dashboard Cite

Type of publicationArticle (peer-reviewed)Link to publisher's version http://dx.doi.org/10.1007/s12274-014-0616-7Access to the full text of the published version may require a subscription. Rights © Tsinghua University Press and Springer-Verlag Berlin Heidelberg2014. This is a pre-print of an article published in Nano Research. hexagonally ordered films were demonstrated using a supercritical fluid process at low temperatures and pressures. Predominant swelling of PEO domain in scCO2 induces nanophase separation. scCO2 serves as green alternative to the conventional organic solvents for the phase segregation of BCPs with complete elimination of any residual solvent in the patterned film.The depressurization rate of scCO2 following annealing was found to affect the morphology of the films. The supercritical annealing conditions could be used to define nanoporous analogues of the microphase separated films without additional processing providing a one-step route to membrane like structures without affecting the ordered surface phase segregated structure. An understanding of the BCP self-assembly mechanism can be realized in terms of the deviation in glass transition temperature, melting point, viscosity, interaction parameter and volume fraction of the constituent blocks in the scCO2 environment.

show abstract

Section: Role Of Scf On Microphase Separationsupporting

confidence: 77%

Section: Microphase Separation Of Higher Molecular Weight Bcpmentioning

confidence: 99%

Section: Role Of Scf On Microphase Separationmentioning

confidence: 99%

See 1 more Smart Citation

Nanophase separation and structural evolution of block copolymer films: A “green” and “clean” supercritical fluid approach

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Qualitatively, the step in the isotherms reflects a narrow and uniform distribution of the pore size. CO 2 swelling of block copolymers has been studied previously by Zhang and Lemert 40 . The authors reported a volume change of up to 25 % for the polymers poly(methyl acrylate) and poly(styrenemethylmethacrylate) block copolymer at pressure of approximately 110 bar.…”

Section: Resultsmentioning

confidence: 99%

Pore Expansion in Mesoporous Silicas Using Supercritical Carbon Dioxide

et al. 2004

View full text Add to dashboard Cite

In this paper we report the controlled expansion of pores within mesoporous silicas using supercritical carbon dioxide (sc-CO 2 ). Our method uses the tunable density of sc-CO 2 to induce the controlled swelling of the triblock copolymer surfactant templating agents, P123 (PEO 20 PPO 69 PEO 20 ) and P85 (PEO 26 PPO 39 PEO 26 ). This swelling process ultimately leads to the control of pore diameters and hexagonal spacing within the mesoporous silicas. At pressures of approximately 482 bar, pore diameters of up to 100 Å can be achieved representing a pore expansion of 54 % compared to the conventionally formed mesoporous silicas. Powder X-ray diffraction (PXRD), transmission electron microscopy (TEM) and nitrogen adsorption techniques were used to establish pore diameters, silica wall widths and the hexagonal packing of the pores within the sc-CO 2 treated mesoporous silicas. The sc-CO 2 was shown not to effect the hexagonal ordering of the silica, a distinct advantage over conventional pore swelling techniques.2

show abstract

“…Another great advantage of working under supercritical media is that the fluids are gases at room temperature and atmospheric pressure. They are rapidly dissipated, leaving no toxic solvent residue behind and can be easily recovered upon release of pressure [9,10]. Finally, due to the environmentally friendly properties of supercritical carbon dioxide, it is possible to substitute toxic organic solvents in several processes.…”

Section: Introductionmentioning

confidence: 99%

Sorption and diffusion of dense carbon dioxide in a biocompatible polymer

Duarte

Martins

Coimbra

et al. 2006

The Journal of Supercritical Fluids

View full text Add to dashboard Cite

Mass sorption and diffusion coefficients in one acrylate biocompatible copolymer contacted with supercritical (sc) carbon dioxide are reported. Equilibrium solubility of dense carbon dioxide in poly(methylmethacrylate-co-ethylhexylacrylate-co-ethyleneglycoldimethacrylate) (P(MMA-EHA-EGDMA)) was studied by a gravimetric method in a temperature range from 308 to 323 K and a pressure range from 10.0 to 20.0 MPa. The cross-linked copolymer presented Fickian behavior and Fick's diffusion model was applied to determine the amount of carbon dioxide present and the diffusion coefficients. Diffusion coefficients for the sorption under supercritical conditions and desorption at ambient conditions were determined and compared. Samples of P(MMA-EHA-EGDMA) with different thickness were used for comparison of the maximum sorption degree. Polymerization conditions were also varied in order to evaluate the influence of the molecular weight of the copolymer in the CO 2 sorption process. To investigate the possibility of impregnating this acrylate copolymer with an anti-inflammatory drug, a preliminary experiment was performed.

show abstract

Sorption and swelling of block copolymers in the presence of supercritical fluid carbon dioxide

Cited by 136 publications

References 50 publications

Nanophase separation and structural evolution of block copolymer films: A “green” and “clean” supercritical fluid approach

Nanophase separation and structural evolution of block copolymer films: A “green” and “clean” supercritical fluid approach

Pore Expansion in Mesoporous Silicas Using Supercritical Carbon Dioxide

Sorption and diffusion of dense carbon dioxide in a biocompatible polymer

Contact Info

Product

Resources

About