@article{han_jeon_ryu_semler_jhon_genzer_2009, title={Discriminating Among Co-monomer Sequence Distributions in Random Copolymers Using Interaction Chromatography}, volume={30}, ISSN={["1521-3927"]}, DOI={10.1002/marc.200900282}, abstractNote={Interaction chromatography has been employed to validate that adsorption of poly[styrene-co-(4-bromostyrene)] (PBr(x) S) random copolymers, where x denotes the mole fraction of 4-bromostyrene (4-BrS) in PBr(x) S in solution depends on the average number of adsorptive segments, the type of adsorbing substrate, and on the co-monomer sequence distribution in PBr(x) S.}, number={18}, journal={MACROMOLECULAR RAPID COMMUNICATIONS}, author={Han, Junwon and Jeon, Byung Ho and Ryu, Chang Y. and Semler, James J. and Jhon, Young K. and Genzer, Jan}, year={2009}, month={Sep}, pages={1543–1548} }
 @article{jhon_semler_genzer_beevers_gus'kova_khalatur_khokhlov_2009, title={Effect of Comonomer Sequence Distribution on the Adsorption of Random Copolymers onto Impenetrable Flat Surfaces}, volume={42}, ISSN={["1520-5835"]}, DOI={10.1021/ma8027936}, abstractNote={We study the effect of comonomer sequence distributions in random copolymers (RCPs) on RCP adsorption on flat impenetrable surfaces. RCP poly(styrene-co-4-bromostyrene) (PBrxS), where x denotes the mole fraction of 4-bromostryrene (4-BrS), is prepared by bromination of parent homopolystyrene. By varying the solvent quality during the bromination, either “truly random” (good solvent) or “random-blocky” (poor solvent) PBrxS RCPs are prepared. Adsorption studies of PBrxS from various solvents at silica surfaces reveal that the adsorption of PBrxS increases with (1) increasing blockiness of the macromolecule, (2) increasing content of 4-BrS in PBrxS, and (3) decreasing solvent quality. Additionally, the effect of comonomer sequence distribution on RCP adsorption is modeled in detail using a coarse-grained statistical mechanical model and fully atomistic simulations based on configurational-biased grand-canonical Monte Carlo (CB-GCMC) technique. The main result from the simulations can be summarized as follows...}, number={7}, journal={MACROMOLECULES}, author={Jhon, Young K. and Semler, James J. and Genzer, Jan and Beevers, Martin and Gus'kova, Olga A. and Khalatur, Pavel G. and Khokhlov, Alexei R.}, year={2009}, month={Apr}, pages={2843–2853} }
 @article{jhon_semler_genzer_2008, title={Effect of solvent quality and chain confinement on the kinetics of polystyrene bromination}, volume={41}, DOI={10.1021/ma8011653}, abstractNote={We report on the kinetics of the bromination of free polystyrene (PS) chains in bulk solution and those anchored on flat solid substrates by performing the bromination reaction in different solvents, including nitrobenzene (NB), 1-chlorodecane (CD), 1-chloroundecane (CUD), and 1-chlorododecane (CDD), at various temperatures. We find that bulk bromination of PS follows the second-order kinetic in bromine and the reaction rate increases with increasing dielectric constant of the solvent (e). In spite of eCDD > eCD, the bulk bromination kinetics of PS in CDD is slower than that in CD because of lower solubility of PS in CDD than in CD. In addition, we demonstrate that the reaction rates for brominating PS brushes anchored to flat solid substrates are much slower than those for brominating free PS chains in bulk solution. We attribute this behavior to steric hindrance due to PS confinement on the substrate.}, number={18}, journal={Macromolecules}, author={Jhon, Y. K. and Semler, J. J. and Genzer, Jan}, year={2008}, pages={6719–6727} }
 @article{semler_jhon_tonelli_beevers_krishnamoorti_genzer_2007, title={Facile method of controlling monomer sequence distributions in random copolymers}, volume={19}, DOI={10.1002/adma.200602359}, abstractNote={Inthis report, we present a simple methodology facilitating theformation of A-B random copolymers with tunable sequencedistributions. We demonstrate that varying the degree ofblockiness in the sequence distribution of A and B monomershas a profound impact on the partition of random copolymersat interfaces.Random copolymers (RCPs) are long chain moleculesmade of covalently bound monomers comprising at least twodifferent chemical moieties (say, A and B). In addition to theoverall molecular weight, RCPs are characterized by theircomposition and monomer sequence distribution. The abilityof A-B RCPs to act as “homopolymers with tunable composi-tion”, ranging between A and B homopolymers, has recentlyattracted considerable attention in controlling polymer misci-bility}, number={19}, journal={Advanced Materials}, author={Semler, J. J. and Jhon, Y. K. and Tonelli, A. and Beevers, M. and Krishnamoorti, R. and Genzer, Jan}, year={2007}, pages={2877-} }
 @article{semler_genzer_2004, title={Monte Carlo simulations of copolymer adsorption at planar chemically patterned surfaces: Effect of interfacial interaction}, volume={13}, ISSN={["1521-3919"]}, DOI={10.1002/mats.200300039}, abstractNote={Monte Carlo simulation utilizing the bond fluctuation model in conjunction with single and configurational biased Monte Carlo moves is used to study the adsorption of diblock (A-block-B) and alternating (A-alt-B) copolymers at flat, chemically heterogeneous surfaces comprising C and D domains. The main objective of this work is to address the effect of the strength of attraction between the adsorbing surface domains, D, and the copolymer adsorbing segments, B, on the copolymer's ability to recognize the chemical pattern on the surface. The results of our simulations reveal that both block and alternating copolymers have the ability to recognize the surface motif and transcribe it into the bulk material. The extent to which diblock copolymers transfer the chemical pattern from the surface to the bulk is relatively unaffected when the attractive B-D potential is increased beyond a certain critical value. This behavior stems from the brush-like conformation adopted by the diblock copolymer at the substrate. In contrast to the diblock copolymer, the adsorption of the alternating copolymer is influenced by the strength of the attraction between the copolymer's adsorbing segments and the adsorbing domains on the surface. Since the B segments are distributed evenly along the backbone, the alternating copolymers are more likely to adopt conformations in which the whole chain is zipped to the surface. The resultant entropic frustration is then alleviated through an increased formation of loops with little change to their length. Such conformational changes endow the alternating copolymer with the ability to invert the substrate pattern as the distance away from the surface is increased.}, number={3}, journal={MACROMOLECULAR THEORY AND SIMULATIONS}, author={Semler, JJ and Genzer, J}, year={2004}, month={Apr}, pages={219–229} }
 @article{semler_genzer_2003, title={Monte Carlo simulations of copolymer adsorption at planar chemically patterned surfaces: Effect of surface domain sizes}, volume={119}, ISSN={["0021-9606"]}, DOI={10.1063/1.1597872}, abstractNote={We present results of Monte Carlo simulation studies utilizing the bond fluctuation model in conjunction with single and configurational biased Monte Carlo moves to investigate the adsorption of diblock (A–b–B) and alternating (A–alt–B) copolymers at physically flat surfaces made of an equal number of two chemically different sites, C and D. The adsorption of the copolymer to the surface is driven by the repulsion between the A and B segments along the copolymer and the attraction between the B segments and the D sites on the surface. We address the critical role of the commensurability between the copolymer’s monomer sequence distribution and the size and spatial distribution of the surface adsorbing sites on the copolymer adsorption. We show that both copolymer architectures have the ability to recognize the surface motif and transcribe it into the bulk material. Diblock copolymers can transfer the pattern once the heterogeneous domain sizes match the size of the parallel component to the radius of gyra...}, number={10}, journal={JOURNAL OF CHEMICAL PHYSICS}, author={Semler, JJ and Genzer, J}, year={2003}, month={Sep}, pages={5274–5280} }
 @article{walker_semler_leonard_maanen_bukovnik_spontak_2002, title={ABA triblock copolymer gels modified with an A-compatible semicrystalline homopolymer}, volume={18}, ISSN={["0743-7463"]}, DOI={10.1021/la026117d}, abstractNote={In the presence of a midblock-selective solvent, ABA triblock copolymers form physical gels in which bridged and entangled B-chains establish a swollen network stabilized by A-microdomains. Here, we seek to improve the properties of an ABA gel through the addition of an A-compatible, high-molecular-weight semicrystalline homopolymer (shA). Dynamic rheology indicates that the elastic modulus increases substantially, and far beyond that achievable with an inert filler, with increasing shA content at constant solvent concentration. Transmission electron micrographs reveal the existence of nanoscale shA filaments and sheets dispersed in a micelle-stabilized gel network. The shape of the nanoscale shA objects, which are partially crystalline according to differential scanning calorimetry, and their apparent interaction with the A-rich micelles enhance network development and are responsible for the pronounced modulus increase.}, number={22}, journal={LANGMUIR}, author={Walker, TA and Semler, JJ and Leonard, DN and Maanen, GJ and Bukovnik, RR and Spontak, RJ}, year={2002}, month={Oct}, pages={8266–8270} }