@article{ISI:000537681700002,
 abstract = {Physical confinement of polymers not only affects their structure but
also modifies their effective interaction profiles. In this article, we
investigate the nature of graphene-adsorbed poly(amidoamine) (PAMAM)
dendrimers' interactions using fully atomistic molecular dynamics
simulations. Using the umbrella sampling technique, we calculate the
potential of mean force (PMF) profiles for the interaction between two
graphene-adsorbed PAMAM dendrimers of generations 3 and 4 as a function
of their protonation levels. We find that the attractive PMF profile
observed for the interaction between two nonprotonated (high pH) PAMAM
dendrimers in bulk becomes repulsive upon adsorption. Also, the
repulsive interdendrimer interactions known in bulk for the protonated
dendrimers become enhanced for the adsorbed case. We further explain
these weakened interactions by explicitly showing that the
dendrimer-graphene interaction is an order of magnitude larger than the
dendrimer-dendrimer bulk interaction. Using the force integration
method, we obtain the contributions from various subinteractions present
in the system, that is, dendrimer-water, dendrimer-ions,
dendrimer-graphene, and dendrimer-dendrimer to the total PMF. From these
contributions, we conclude that the reduced dendrimer-dendrimer
interactions in the adsorbed case, as compared to those in bulk, lead to
the enhanced repulsive effective interdendrimer interactions. Our PMF
profiles fit well with the sum of exponential and Gaussian functions,
proposed in the bulk interdendrimer interaction study. We hope the
current results provide the microscopic origin of how adsorption weakens
the interpolymer interactions in general.},
 author = {Gosika, Mounika and Mandal, Taraknath and Maiti, Prabal K.},
 doi = {10.1021/acs.langmuir.0c00208},
 issn = {0743-7463},
 journal = {LANGMUIR},
 month = {MAY 26},
 number = {20},
 orcid-numbers = {Gosika, Mounika/0000-0002-6996-2051
Maiti, Prabal K/0000-0002-9956-1136},
 pages = {5492-5501},
 times-cited = {0},
 title = {Modulating Interdendrimer Interactions through Surface Adsorption},
 unique-id = {ISI:000537681700002},
 volume = {36},
 year = {2020}
}