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Gregory C. Rutledge and Samuel M. Allen. Đjurdjević, Predrag (Predrag Dragutin) Massachusetts Institute of Technology. Department of Materials Science and Engineering. Massachusetts Institute of Technology. Department of Materials Science and Engineering 2013-07-10T14:54:27Z 2013-07-10T14:54:27Z 2013 2013 http://hdl.handle.net/1721.1/79557 851443257 Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013. Title as it appears in MIT degrees awarded booklet, September 2012: Molecular simulation of primary nucleation and growth from oriented melts in polyethylene. Cataloged from PDF version of thesis. Includes bibliographical references (p. 59-63). The enhancement of the primary flow-induced nucleation rate in short chain alkanes (C20 and C150) has been examined for different levels of orientation by atomistic molecular dynamics simulations. The nucleation rate has been found to change drastically by varying average molecular orientation and temperature. For example, it is possible to accelerate nucleation kinetics by three orders of magnitude at the same temperature, but varying the average level of orientation (P2 (cos [Theta])) . The size of the critical nucleus has been found to increase with the level of undercooling Tm - T decrease, consistent with the classical nucleation theory. Our atomnistic molecular dynamics simulation model is even tractable at the small levels of undercooling, thus clearly demonstrating the effects of orientation (melt anisotropy) on nucleation kinetics when thermal nucleation is expected to be negligible. Furthermore, we calculate the influence of melt anisotropy on the growth rate. As expected, the growth rate is also altered by melt anisotropy. Furthermore, the growth rate maximum always occurs at the temperature above the nucleation kinetics maximum. by Predrag Đjurdjević. S.M. 63 p. eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Materials Science and Engineering. Molecular dynamics modeling of orientation-induced nucleation in short alkanes : toward molecular modeling of flow-induced crystallization in polymers Molecular simulation of primary nucleation and growth from oriented melts in polyethylene Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="d460402c-f67d-4339-b4c1-305aae922cc0"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Molecular dynamics modeling of orientation-induced nucleation in short alkanes : toward molecular modeling of flow-induced crystallization in polymers</Title> <Subtitle>Molecular simulation of primary nucleation and growth from oriented melts in polyethylene</Subtitle> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2013</PublicationDate> <Authors> <Author> <DisplayName>Đjurdjević, Predrag (Predrag Dragutin)</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Materials Science and Engineering.</Keyword> <Abstract>The enhancement of the primary flow-induced nucleation rate in short chain alkanes (C20 and C150) has been examined for different levels of orientation by atomistic molecular dynamics simulations. The nucleation rate has been found to change drastically by varying average molecular orientation and temperature. For example, it is possible to accelerate nucleation kinetics by three orders of magnitude at the same temperature, but varying the average level of orientation (P2 (cos [Theta])) . The size of the critical nucleus has been found to increase with the level of undercooling Tm - T decrease, consistent with the classical nucleation theory. Our atomnistic molecular dynamics simulation model is even tractable at the small levels of undercooling, thus clearly demonstrating the effects of orientation (melt anisotropy) on nucleation kinetics when thermal nucleation is expected to be negligible. Furthermore, we calculate the influence of melt anisotropy on the growth rate. As expected, the growth rate is also altered by melt anisotropy. Furthermore, the growth rate maximum always occurs at the temperature above the nucleation kinetics maximum.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>