Unfolding of collapsed polymers in shear flow: Effects of colloid banding structures in confining channels
Using hydrodynamic simulations, we demonstrate that confined colloidal suspensions can greatly enhance the unfolding of collapsed single polymers in flow. When colloids come in direct contact with the polymers due to the flow, the collapsed chains become flattened or elongated on the surface of the...
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| Format: | Article |
| Language: | en_US |
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American Physical Society
2014
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| Online Access: | http://hdl.handle.net/1721.1/89036 https://orcid.org/0000-0001-5554-1283 |
| _version_ | 1826206601056354304 |
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| author | Chen, Hsieh Alexander-Katz, Alfredo |
| author2 | Massachusetts Institute of Technology. Department of Materials Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Materials Science and Engineering Chen, Hsieh Alexander-Katz, Alfredo |
| author_sort | Chen, Hsieh |
| collection | MIT |
| description | Using hydrodynamic simulations, we demonstrate that confined colloidal suspensions can greatly enhance the unfolding of collapsed single polymers in flow. When colloids come in direct contact with the polymers due to the flow, the collapsed chains become flattened or elongated on the surface of the colloids, increasing the probability of forming large chain protrusions that the flow can pull out to unfold the polymers. This phenomenon may be suppressed if the colloid size is commensurate with the confining channels, where the colloids form well-defined banding structures. Here, we analyze the colloid banding structures in detail and their relation to the chain unfolding. We find that for colloid volume fractions up to 30%, the confined colloids form simple cubic (sc), hexagonal (hex), or a mixture of sc + hex structures. By directly changing the heights of the confining channels, we show that the collapsed polymers unfold the most in the mixed sc + hex structures. The diffuse (not well-defined) bands in the mixed sc + hex structures provide the highest collision probability for the colloids and the polymers, thus enhancing unfolding the most. Without colloidal suspensions, we show that the confining channels alone do not have an observable effect on the unfolding of collapsed polymers. The well-defined colloid bands also suppress the unfolding of noncollapsed polymers. In fact, the average size for noncollapsed chains is even smaller in the well-defined bands than in a channel without any colloids. The appearance of well-defined bands in this case also indicates that lift forces experienced by the polymers in confinement are negligible compared to those exerted by the colloidal band structures. Our results may be important for understanding the dynamics of mixed colloid polymer solutions. |
| first_indexed | 2024-09-23T13:35:29Z |
| format | Article |
| id | mit-1721.1/89036 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T13:35:29Z |
| publishDate | 2014 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/890362022-09-28T14:52:14Z Unfolding of collapsed polymers in shear flow: Effects of colloid banding structures in confining channels Chen, Hsieh Alexander-Katz, Alfredo Massachusetts Institute of Technology. Department of Materials Science and Engineering Chen, Hsieh Alexander-Katz, Alfredo Using hydrodynamic simulations, we demonstrate that confined colloidal suspensions can greatly enhance the unfolding of collapsed single polymers in flow. When colloids come in direct contact with the polymers due to the flow, the collapsed chains become flattened or elongated on the surface of the colloids, increasing the probability of forming large chain protrusions that the flow can pull out to unfold the polymers. This phenomenon may be suppressed if the colloid size is commensurate with the confining channels, where the colloids form well-defined banding structures. Here, we analyze the colloid banding structures in detail and their relation to the chain unfolding. We find that for colloid volume fractions up to 30%, the confined colloids form simple cubic (sc), hexagonal (hex), or a mixture of sc + hex structures. By directly changing the heights of the confining channels, we show that the collapsed polymers unfold the most in the mixed sc + hex structures. The diffuse (not well-defined) bands in the mixed sc + hex structures provide the highest collision probability for the colloids and the polymers, thus enhancing unfolding the most. Without colloidal suspensions, we show that the confining channels alone do not have an observable effect on the unfolding of collapsed polymers. The well-defined colloid bands also suppress the unfolding of noncollapsed polymers. In fact, the average size for noncollapsed chains is even smaller in the well-defined bands than in a channel without any colloids. The appearance of well-defined bands in this case also indicates that lift forces experienced by the polymers in confinement are negligible compared to those exerted by the colloidal band structures. Our results may be important for understanding the dynamics of mixed colloid polymer solutions. National Science Foundation (U.S.) (CAREER Award 1054671) DuPont (Firm) (Fellowship) 2014-08-25T18:21:43Z 2014-08-25T18:21:43Z 2014-03 2014-03 Article http://purl.org/eprint/type/JournalArticle 1539-3755 1550-2376 http://hdl.handle.net/1721.1/89036 Chen, Hsieh, and Alfredo Alexander-Katz. “Unfolding of Collapsed Polymers in Shear Flow: Effects of Colloid Banding Structures in Confining Channels.” Phys. Rev. E 89, no. 3 (March 2014). © 2014 American Physical Society https://orcid.org/0000-0001-5554-1283 en_US http://dx.doi.org/10.1103/PhysRevE.89.032602 Physical Review E Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society American Physical Society |
| spellingShingle | Chen, Hsieh Alexander-Katz, Alfredo Unfolding of collapsed polymers in shear flow: Effects of colloid banding structures in confining channels |
| title | Unfolding of collapsed polymers in shear flow: Effects of colloid banding structures in confining channels |
| title_full | Unfolding of collapsed polymers in shear flow: Effects of colloid banding structures in confining channels |
| title_fullStr | Unfolding of collapsed polymers in shear flow: Effects of colloid banding structures in confining channels |
| title_full_unstemmed | Unfolding of collapsed polymers in shear flow: Effects of colloid banding structures in confining channels |
| title_short | Unfolding of collapsed polymers in shear flow: Effects of colloid banding structures in confining channels |
| title_sort | unfolding of collapsed polymers in shear flow effects of colloid banding structures in confining channels |
| url | http://hdl.handle.net/1721.1/89036 https://orcid.org/0000-0001-5554-1283 |
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