Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Colloidal stabilization of graphene sheets by ionizable amphiphilic
  block copolymers in various media   In this work, linear polystyrene-poly(2-vinylpyridine) (PS-b-P2VP) and
heteroarm star PS_22P2VP_22 ionizable block copolymers were used as dispersing
agents for the liquid-phase exfoliation of pristine graphene. Various
strategies such as direct exfoliation, film hydration and phase transfer have
been employed and compared. The best strategy involved a two-step process,
namely, pre-exfoliation of graphite in polymer/CHCl3 solutions followed by
phase transfer to acidified water. High concentrations of stable aqueous
suspensions of graphene flakes, highly enriched in monolayer structures, were
then obtained by using the star-shaped copolymers as stabilizers. The
as-prepared graphene/copolymer hybrids were used as a filler material in order
to prepare functional polymer composites for mechanical reinforcement. Such
copolymer-modified graphene sheets have proven to be efficient reinforcing
agents of PVA, as a significant increase of storage modulus (145% higher than
that of neat PVA) was achieved even at a low graphene weight fraction of 0.1
wt%.

5
The categories of this paper are: gr-qc
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The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs